CHASSIS ELECtRldAL 6-9
93156g27 Fig. 21 Exploded view of the blower motor
and related components-1999-00 Galant
To install:
6. Check the inside of the case carefully; any
debris can snag the fan and cause noise or poor air-
flow.
7. Install the blower motor, in the blower case
and secure with the three mounting bolts,
8. Attach the blower motor electrlcal connector,
9. Install the compressor module, if removed.
10. Install the undercover, takmg care to insure it
is in place and all the fasteners are secure.
11. Connect the negative battery cable.
Diamante
u See Figures 22 and 23
1. Disarm the air bag, as outlined earlier in this
section.
Wait at least 1 minute before working on the
vehicle. The air bag system is designed to
retain enough voltage to deploy the air bag
for a short period of time even after the bat-
tery has been disconnected.
2. Remove the passenger side lower instrument
panel and shower duct,
3. Remove the glove box striker, glove box,
glove box outer casing and the screw below the as-
sembly.
4. Remove the evaporator case mounting bolt
and nut.
5. Remove the inside/outside air changeover
damper motor assembly.
6 Remove the PCM, mounting bracket and MFI
control relay.
7. Remove the instrument panel passengers
side lower bracket.
8. Remove the molded hose from the blower as-
sembly.
9. Remove the blower motor assembly.
10. Remove the fan retaining nut and fan in order
to replace the motor,
To install: 11. Check that the blower motor shaft is not bent
and that the packing is in good condition, Clean all
parts of dust, etc.
12. Assemble the motor and fan. Install the
blower motor then attach the connector.
13. Install the molded hose. Install the duct or
undercover.
14. Install the evaporator case mounting bolt and
nut. 15. Install the instrument panel passengers side
lower bracket.
16. Install the PCM, mounting bracket and MFI
control relay.
17. Install the inside/outside air changeover
damper motor assembly.
18. Install the screw below the glove box assem-
bly, and the entire glove box unit.
19. Install the lower instrument panel and shower
duct.
20. Connect the negative battery cable and check
the entire climate control system for proper opera-
tion.
REMOVAL & INSTALLATION
Diamante
u See Figures 24
and 25
1. Disarm the air bag Refer to the procedure
earlier in this section.
2. Dram the cooling system and disconnect the
heater hoses from the core tubes. Plug the hoses.
3. Remove the passenger side undercover.
4. Remove the right side foot shower duct. 5. To remove the console, remove the ashtray
and remove the revealed screw. Then remove the 4
screws from the sides of the assembly and remove.
6. Remove the decorative plugs from the drl-
ver’s knee protector. Remove the revealed screws, the
knee protector assembly and the protector support
bracket.
7. Remove the steering column covers.
8. Remove the glove box striker, glove box,
glove box outer casing and the screw below the as-
sembly.
9. Remove the radio bezel and the stereo enter-
tainment system.
10. Remove the climate control system control
head.
11. Remove the cup holder.
12. Remove the speakers from the top of the in-
strument panel.
13. Remove the instrument cluster bezel and the
instrument cluster.
14. To remove the speedometer cable adapter
from the instrument panel, first disconnect the
speedometer cable from the transaxle. Then unlock
the adapter from the instrument panel, pull the
speedometer cable slightly inwards, and remove the
adapter
15. Detach all steering column connectors, re-
move the column mounting bolts, and allow the
steering column to rest on the front seat. Be very
Fig. 23 Exploded view of the blower motor
and related components-1997-00 Dia-
Fig. 25 Heater core and related components
exploded view-1997-00 Diamante
6-14 CHASSIS ELECTRICAL
CRUISE CONTROL TROUBLESHOOTING Problem Posable Cause
WIII not hold proper speed 1 Incorrect cable adjustment
F.~. _I.~_ - 1L .-AL‘- I. I -
Cruise intermittently cuts out
trrnarng Inrome nnKage Leaking vacuum servo diaphragm
Leaking vacuum tank
Faulty vacuum or vent valve
Faulty stepper motor
Faulty transducer
Faulty speed sensor
Faulty cruise control module
‘ Clutch or brake switch adjustment too tight -chnrt *r nna* in the cruise control circuit
cer VI I”, . vt “y”‘,
I- Faulty transdu
Leaking vacuum circuit Faulty cruise control switch
Faulty stepper motor
Note. Use this chart as a guide. Not all systems will use the components listed.
t-,
I ,-- ,
REMOVAL&INSTALLATION
# See Figures 32 thru 40, 46 and 47
1. Disconnect battery negative cable.
*If equipped with an air bag, be sure to dis-
arm it before entering the vehicle.
2. Remove the panel from around the radio, On
some models the panel is retained with screws, On
others, use a plastic trim tool to pry the lower pad of
the radio panel loose.
3. Remove the radio/tape/CD player mounting
bracket retaining screws, 4. Slide the radio chassis out of the instrument
*panel and disconnect the radio wiring harness and
*Depending on the speaker installation, it
may save time at installation to identify and
tag all wires before they are disconnected.
5. Remove the mounting brackets from the radio.
To install:
6. The installation is the reverse of the removal
procedure. Make all electrical and antenna connec-
tions before fastening the radio assembly in place.
7. Test all functions of the entertainment system
prior to final installation. If all are satisfactory, install
the unit and center panel.
8. Connect the negative battery cable and recheck
the entire system for proper operation. CD Changer
1. Disconnect the negative battery cable.
2. Open the trunk lid.
3. Remove any necessary trim to access the CD
changer.
4. Remove the CD-changer-to-bracket retaining
screws.
5. Lift the changer from the bracket and detach
the electrical connectors.
6. Remove the changer from the vehicle.
To install:
7. The installation is the reverse of removal.
REMOVAL&INSTALLATION l
Front (Instrument Panel Mounted) Speaker
u See Figure 48
1. Disconnect the negative battery cable.
2. Remove the front speaker garnish.
3. Remove the retainers, detach the harness con-
nector and remove the front speaker,
Handle the speaker carefully to avoid dam-
aging the cone during removal and installa-
tion.
4. Installation is the reverse of the removal proce-
dure
- 8-38 SUSPENSION AND STEERING
11. Adjust the power steering belt for proper ten-
sion and tighten the adjusting bolts.
12. Reconnect the negative battery cable.
13. Refill the reservoir and bleed the system.
3. Of EIJGINE
1. Disconnect the battery negative cable. 2. Disconnect the return fluid line. Remove the
reservoir cap and allow the return line to drain the
fluid from the reservoir. If the fluid is contaminated,
disconnect the ignition high tension cable and crank
the engine several times to drain the fluid from the
gear box.
3. Remove the power steering pump drive belt.
4. Remove the pressure switch connector from
the side of the pump.
5. If the alternator is located under the oil pump,
cover it with a shop towel to protect it from oil.
6. Disconnect the high pressure hose and the
return hose from the pump.
7. Remove the pump drive belt and unbolt the
pump from its bracket and remove the pump.
To install: 8. Install the pump, *rap the belt around the
pulley and tighten the bolts that secure the pump to
17 ft. Ibs. (24 Nm).
9. Replace the O-rings and connect the high
pressure hose. Connect the pressure line so the
notch in the fitting aligns and contacts the pump’s
guide bracket. Tighten the mounting nut with lock-
washer to 17 ft. Ibs. (24 Nm).
IO. Using a new hose clamp, connect the return
line.
11. Attach the pressure switch connector.
12. Adjust the belt tension and tighten the
adjust- ing bolts.
13. Refill the reservoir and bleed the system.
Diamante *
FRONT
. 1. Disconnect the battery negative cable. 2. Disconnect the return fluid line. Remove the
reservoir cap and allow the return line to drain the
fluid from the reservoir. If the fluid is contaminated,
disconnect the ignition high tension cable and crank
the engine several times to drain the fluid from the
gearbox.
3. Remove the power steering pump drive belt.
4. Remove the pressure switch connector from
the side of the pump.
5. If the alternator is located under the oil pump,
cover it with a shop towel to protect it from oil.
6. Disconnect the high pressure hose and the
return hose from the pump.
7. Remove the pump drive belt and unbolt the
pump from its bracket and remove the pump.
To install: 8. Install the pump, wrap the belt around the
pulley and tighten the bolts that secure the pump to
17 ft. Ibs. (24 Nm).
9. Replace the O-rings and connect the high
pressure hose. Connect the pressure line so the
notch in the fitting aligns and contacts the pump’s
guide bracket. Tighten the mounting nut with lock-
washer to 17 ft. Ibs. (24 Nm).
10. Using a new hose clamp, connect the return
line.
Il. Attach the pressure switch connector.
12. Adjust the belt tension and tighten the adjust-
ing bolts.
13. Refill the reservoir and bleed the system.
REAR
1. Disconnect the negative battery cable.
2. Drain the power steering fluid.
3. Remove the rear power steering pump heat
protector, located on the engine side of the differen-
tial on the transaxle.
4. Disconnect the pressure line from the pump.
5. Disconnect the suction hose from the pump.
6. Remove the mounting bolts and remove the
pump from the transaxle.
44
33
REMOVAL STEPS
5. POWER STEERING PUMP
BRACKET STAY
6. OIL PUMP 1. DRIVE-BELT
2. SUCTION HOSE I ’ 3. PRESSURE HOSE
4. PRESSURE SWITCH
CONNECTOR
Exploded view of the power steering pump-Diamante
. 93158ga5
7. The installation is the reverse of the removal
procedure. Tighten the mounting bolts to 17 ft. Ibs.
(24 Nm).
8. Refill the reservoir and bleed the system.
Extreme caution should be taken when test-
ing the rear steering pump. Ensure that the
vehicle is supported safely and that all com-
ponents are torqued to specification prior be
testing.
. SYSTEM BLEEDING
,Front
1. Raise the vehicle and support safely.
2. Manually turn the pump pulley a few times.
3. Turn the steering wheel all the way to the left
and to the right 5 or 6 times.
4. Disconnect the ignition high tension cable
and, while operating the starter motor intermittently,
turn the steering wheel all the way to the letI and right
5-6 times for 15-20 seconds. During bleeding,
make sure the fluid in the reservoir never falls below
the lower position of the filter. If bleeding is at-
tempted with the engine running, the air will be ab-
sorbed in the fluid. Bleed only while cranking.
5. Connect ignition high tension cable, start en-
gine and allow to idle.
6. Turn the steering wheel left and right until
there are no air bubbles in the reservoir. Confirm that
the fluid is not milky and the level is up to the speci-
fied position on the gauge. Confirm that there is very
little change in the fluid level when the steering wheel
is turned. If the fluid level changes more than 0.2 in.
(5mm), the air has not been completely bled. Repeat
the process.
Rear
.
1. Bleed the front steering system.
2. Start the engine and let it idle.
3. Loosen the bleeder screw on the left side of the
control valve and install special tool MB991230 to
the bleeder.
4. Turn the steering wheel all the way to the left,
then immediately turn it halfway back. Confirm that
air has discharged with the fluid.
5. Repeat Step 4 two or three times as required,
to remove all air from the rear system. Stop the en-
gine.
6. Loosen the power cylinder (rear steering gear)
bleeder screw about I/* turn and install the same
special tool with the rotation prevention metal fixtures
to prevent the bleeder from opening more.
7. Start the engine and run to 50 mph to circulate
the fluid.
8. Maintain a speed of 20 mph and turn the steer-
ing wheel back and forth. Air should be discharged ,
through the tube of the special tool and into the oil
reservoir.
9. Repeat until all air is removed from the power
cylinder.
9-2 BRAKES
Hydraulic systems are used to actuate the brakes
of all modern automobiles. The system transports the
power required to force the frictional surfaces of the
braking system together from the pedal to the indi-
vidual brake units at each wheel. A hydraulic system
is used for two reasons.
First, fluid under pressure can be carried to all
parts of an automobile by small pipes and flexible
hoses without taking up a significant amount of room
or posing routing problems.
Second, a great mechanical advantage can be
given to the brake pedal end of the system, and the
foot pressure required to actuate the brakes can be
reduced by making the surface area of the master
cylinder pistons smaller than that of any of the pis-
tons in the wheel cylinders or calipers.
The master cylinder consists of a fluid reservoir
along with a double cylinder and piston assembly.
Double type master cylinders are designed to sepa-
rate the front and rear braking systems hydraulically
in case of a leak. The master cylinder converts me-
chanical motion from the pedal into hydraulic pres-
sure within the lines. This pressure is translated back
into mechanical motion at the wheels by either the
wheel cylinder (drum brakes) or the caliper (disc
brakes).
Steel lines carry the brake fluid to a point on the
vehicle’s frame near each of the vehicle’s wheels. The
fluid is then carried to the calipers and wheel cylin-
ders by flexible tubes in order to allow for suspen-
sion and steering movements.
In drum brake systems, each wheel cylinder con-
tains two pistons, one at either end, which push out-
ward in opposite directions and force the brake shoe
into contact with the drum.
In disc brake systems, the cylinders are part of the
calipers. At least one cylinder in each caliper is used
to force the brake pads against the disc.
All pistons employ some type of seal, usually
made of rubber, to minimize fluid leakage. A rubber
dust boot seals the outer end of the cylinder against
dust and dirt. The boot fits around the outer end of
the piston on disc brake calipers, and around the
brake actuating rod on wheel cylinders.
The hydraulic system operates as follows: When at
rest, the entire system, from the piston(s) in the mas-
ter cylinder to those in the wheel cylinders or
calipers, is full of brake fluid. Upon application of the
brake pedal, fluid trapped in front of the master cylin-
der piston(s) is forced through the lines to the wheel
cylinders. Here, it forces the pistons outward, in the
case of drum brakes, and inward toward the disc, in
the case of disc brakes. The motion of the pistons is
opposed by return springs mounted outside the
cylinders in drum brakes, and by spring seals, in disc
brakes.
Upon release of the brake pedal, a spring located
inside the master cylinder immediately returns the
master cylinder pistons to the normal position. The
pistons contain check valves and the master cylinder
I
has compensating ports drilled in it. These are un-
covered as the pistons reach their normal position.
The piston check valves allow fluid to flow toward the
wheel cylinders or calipers as the pistons withdraw.
Then, as the return springs force the brake pads or
shoes into the released position, the excess fluid
reservoir through the compensating ports. It is during the time the pedal is in the released position that any
fluid that has leaked out of the system will be re-
placed through the compensating ports.
Dual circuit master cylinders employ two pistons,
located one behind the other, in the same cylinder.
The primary piston is actuated directly by mechanical
linkage from the brake pedal through the power
booster. The secondary piston is actuated by fluid
trapped between the two pistons. If a leak develops in
front of the secondary piston, it moves forward until it
bottoms against the front of the master cylinder, and
the fluid trapped between the pistons will operate the
rear brakes. If the rear brakes develop a leak, the pri-
mary piston will move forward until direct contact
with the secondary piston takes place, and it will
force the secondary piston to actuate the front brakes.
In either case, the brake pedal moves farther when the
brakes are applied, and less braking power is avail-
able.
All dual circuit systems use a switch to warn the
driver when only half of the brake system is opera-
tional. This switch is usually located in a valve body
which is mounted on the firewall or the frame below
the master cylinder. A hydraulic piston receives pres-
sure from both circuits, each circuits pressure being
applied to one end of the piston. When the pressures
are in balance, the piston remains stationary. When
one circuit has a leak, however, the greater pressure
in that circuit during application of the brakes will
push the piston to one side, closing the switch and
activating the brake warning light.
In disc brake systems, this valve body also con-
tains a metering valve and, in some cases, a propor-
tioning valve. The metering valve keeps pressure
from traveling to the disc brakes on the front wheels
until the brake shoes on the rear wheels have con-
tacted the drums, ensuring that the front brakes will
never be used alone. The proportioning valve con-
trols the pressure to the rear brakes to lessen the
chance of rear wheel lock-up during very hard brak-
ing.
Warning lights may be tested by depressing the
brake pedal and holding it while opening one of the
wheel cylinder bleeder screws. If this does not cause
the light to go on, substitute a new lamp, make conti-
nuity checks, and, finally, replace the switch as nec-
essary.
The hydraulic system may
be checked for leaks by applying pressure to the pedal gradually and steadily.
If the pedal sinks very slowly to the floor, the system
has a leak. This is not to be confused with a springy
or spongy feel due to the compression of air within
the lines. If the system leaks, there will be a gradual
change in the position of the pedal with a constant
pressure.
Check for leaks along all lines and at wheel cylin-
ders. If no external leaks are apparent, the problem is
inside the master cylinder,
DISC BRAKES
Instead of the traditional expanding brakes that
press outward against a circular drum, disc brake
systems utilize a disc (rotor) with brake pads posi-
tioned on either side of it. An easily-seen analogy is
the hand brake arrangement on a bicycle. The pads
squeeze onto the rim of the bike wheel, slowing its
motion. Automobile disc brakes use the identical principle but apply the braking effort to a separate
disc instead of the wheel.
The disc (rotor) is a casting, usually equipped with
cooling fins between the two braking surfaces. This
enables air to circulate between the braking surfaces
making them less sensitive to heat buildup and more
resistant to fade. Dirt and water do not drastically af-
fect braking action since contaminants are thrown off
by the centrifugal action of the rotor or scraped off
the by the pads. Also, the equal clamping action of
the two brake pads tends to ensure uniform, straight
line stops. Disc brakes are inherently self-adjusting.
There are three general types of disc brake:
1. A fixed caliper.
2. A floating caliper.
3. A sliding caliper.
The fixed caliper design uses two pistons
mounted on either side of the rotor (in each side of
the caliper). The caliper is mounted rigidly and does
not move.
The sliding and floating designs are quite similar.
In fact, these two types are often lumped together. In
both designs, the pad on the inside of the rotor is
moved into contact with the rotor by hydraulic force.
The caliper, which is not held in a fixed position,
moves slightly, bringing the outside pad into contact
with the rotor. There are various methods of attaching
floating calipers. Some pivot at the bottom or top,
and some slide on mounting bolts. In any event, the
end result is the same.
DRUM BRAKES
Drum brakes employ two brake shoes mounted on
a stationary backing plate. These shoes are posi-
tioned inside a circular drum which rotates with the
wheel assembly. The shoes are held in place by
springs. This allows them to slide toward the drums
(when they are applied) while keeping the linings and
drums in alignment. The shoes are actuated by a
wheel cylinder which is mounted at the top of the
backing plate. When the brakes are applied, hydraulic
pressure forces the wheel cylinder’s actuating links
outward. Since these links bear directly against the
top of the brake shoes, the tops of the shoes are then
forced against the inner side of the drum. This action
forces the bottoms of the two shoes to contact the
brake drum by rotating the entire assembly slightly
(known as servo action). When pressure within the
wheel cylinder is relaxed, return springs pull the
shoes back away from the drum.
Most modern drum brakes are designed to self-
adjust themselves during application when the vehi-
cle is moving in reverse. This motion causes both
shoes to rotate very slightly with the drum, rocking
an adjusting lever, thereby causing rotation of the ad-
justing screw. Some drum brake systems are de-
signed to self-adjust during application whenever the
brakes are applied. This on-board adjustment system
reduces the need for maintenance adjustments and
keeps both the brake function and pedal feel satisfac-
tory.
POWER BOOSTERS
Virtually all modern vehicles use a vacuum as-
sisted power brake system to multiply the braking
force and reduce pedal effort. Since vacuum is always
available when the engine is operating, the system is
BRAKES 9-25
Diagnostic inspection item Diagnostic content
trouble
code No.
11 Right front wheel speed sensor
12 Left front wheel speed sensor Open circuit
13 Right rear wheel speed sensor
14 Left rear wheel speed sensor
Abnormal output signal
Abnormal battery posi-
tive voltage 15 Wheel speed sensor system
16 Power supply system
r 21
I Right front wheel speed sensor 1 Excessive gap
22 I Left front wheel speed sensor or short circuit
23 Right rear wheel speed sensor
24 Left rear wheel speed sensor
36 Stop light switch system Open circuit or ON mal-
function
Right front solenoid valve system
I 5’ I Valve relay system 1 Valve relay OFF failure
I 53 1 Motor relay or motor system Motor relay OFF failure
and motor drive failure
63 ABS-ECU Malfunction in ABS-
ECU (program maze,
etc.)
I
!
Detection
conditions
B ’
A, B
A, B
A, B
A, 8
B
A, B
Detection conditions
A: During system check immediately after starting
B: When driving
89579954 Fig. 117 ABS diagnostic trouble code list-1992-96 Diamante
Diagnostrc
trouble Inspection item Detectron
code no. condalons
1
11 1 Front right wheel speed SensOr
I
I I
12 1 Front left wheel speed sensor
13 1 Rear right wheel speed sensor Open circuit
lBsC I
14
Rear left wheel speed sensor
15 Wheel speed sensor output signal abnormal
16 Power supply system
21 Front right wheel speed sensor A B
A, B, C
22 Front left wheel speed sensor
23 Rear right wheel speed sensor
24 Rear left wheel speed sensor
38 Stop light switch system Short circuit
8, c
B. C
41 1 Front right solenoid valve (inlet)
I I
42
Front left solenoid valve (inlet)
43 Rear right solenord valve (inlet) 0.c
44 Rear left solenoid valve (inlet)
45 Front right solenoid valve (outlet)
46 Front left solenoid valve (outlet)
47
Rear nght solenoid valve (outret) - B,C
48 Rear left solenoid valve (outlet)
51
Valve relay A 6, c
53
Motor relay B
63 ABSECU A B, c
Detection conditions
A: During system check immediately after starting 6: While ABS control is not operating while driving C: While ABS control is operating 93159go4 Fig. 118 ABS diagnostic trouble code list-1997-00 Diamante
The ABS control unit performs system tests and
self-tests during startup and normal operation. The
valves, wheel sensors and fluid level circuits are
monitored for proper operation. If a fault is found, the ABS will be deactivated and the amber ANTI LOCK
light will be lit until the ignition is turned OFF. When
the light is lit, the Diagnostic Trouble Code (DTC)
may be obtained. Under normal operation, the ANTI-
89579g53 Fig. 119 ABS diagnostic trouble code list-
1990-93 Galant
LOCK warning lamp will flash either twice (FWD) or 4
times (AWD) vehicles, in about 1 second with the ig-
,
nition switch ON , then the lamp will turn OFF.
The Diagnostic Trouble Codes (DTC) are an al-
phanumeric code and a scan tool, such as DRB-III,
MUT-II or equivalent diagnostic scan tool, is required
to retrieve the codes. Refer to the scan tool manufac-
turers instructions for operating the tool and retriev-
ing the codes.
The Data Link Connector (DLC) for the ABS is lo-
cated under the dash on the driver’s side. It is the
same connector used for the electronic engine con-
trol system.
REMOVALANDINSTALLATION
The Hydraulic Control Unit (HCU) is located in the
engine compartment. It contains the solenoid valves
and the pump/motor assembly which provides pres-
surized fluid for the anti-lock system when necessary.
Hydraulic units are not interchangeable on any vehi-
cles Neither unit is serviceable; if any fault occurs
within the hydraulic unit, the entire unit must be re-
placed.
Diamante
b See Figure 124
1. Disconnect the negative battery cable.
2. Remove the splash shield from beneath the
vehicle.
3. Use a syringe or similar device to remove as
much fluid as possible from the reservoir. Some fluid
will be spilled from lines during removal of the hy-
draulic unit; protect adjacent painted surfaces.
Brake fluid contains polyglycol ethers and
poly9lycols. Avoid contact with the eyes and
wash your hands thoroughly after handling
brake fluid. If you do 9et brake fluid in your
eyes, flush your eyes with clean, running wa-
ter for 15 minutes. If eye irritation persists,
or if you have taken brake fluid internally,
IMMEDIATELY seek medical assistance.
4. Lift the relay box with the harness attached
and position it aside.
5. Remove the air intake duct.
6. Disconnect the brake lines from the hydraulic
unit. Correct reassembly is critical. Label or identify
the lines before removal. Plug each line immediately
TROUBLESHOOTING 11-13
NOTE: When one shock fails, ft is recommended to replace front or rear
units as pairs.
3. Vehicle leans excessively in turns
a. Check for worn or leaking shock absorbers or strut assemblies and replace as neces-
sary.
b. Check for missing, damaged, or worn stabilizer links or bushings, and replace or in-
stall as necessary.
4. Vehicle ride quality seems excessively ha&h
a. Check for seized shock absorbers or strut assemblies and replace as necessary.
b. Check for excessively high tire pressures and adjust pressures to vehicle recommen-
dations.
5. Vehicle seems low or leans to one side
a. Check for a damaged, broken or weak spring. Replace defective parts and check for a
needed alignment.
b. Check for seized shock absorbers or strut assemblies and replace as necessary.
c. Check for worn or leaking shock absorbers or strut assemblies and replace as neces-
sary.
Noises 1. Vehicle makes a clicking noises when driven
a. Check the noise to see if it varies with road speed. Verify if the noise is present when
coasting or with steering or throttle input. If the clicking noise frequency changes with
road speed and is not affected by steering or throttle input, check the tire treads for a
stone, piece of glass, nail or another hard object imbedded into the tire or tire tread.
Stones rarely cause a tire puncture and are easily removed. Other objects may create
an air leak when removed. Consider having these objects removed immediately at a
facility equipped to repair tire punctures.
b. If the clicking noise varies with throttle input and steering, check for a worn Constant
Velocity (CV-joint) joint, universal (U- joint) or flex joint.
2. Vehicle makes a clunking or knocking noise over bumps
a. A clunking noise over bumps is most often caused by excessive movement or clear-
ance in a suspension component. Check the suspension for soft, cracked, damaged or
worn bushings. Replace the bushings and check the vehicle’s alignment.
b. Check for loose suspension mounting bolts. Check the tightness on subframe bolts,
pivot bolts and suspension mounting bolts, and torque to specification.
c. Check the vehicle for a loose wheel bearing. Some wheel bearings can be adjusted for
looseness, while others must be replaced if loose. Adjust or replace the bearings as
recommended by the manufacturer.
d. Check the door latch adjustment. If the door is slightly loose, or the latch adjustment
is not centered, the door assembly may create noises over bumps and rough surfaces.
Properly adjust the door latches to secure the door. 3. Vehicle makes a low pitched rumbling noise when driven
a. A low pitched rumbling noise is usually caused by a drive train related bearing and is
most often associated with a wheel bearing which has been damaged or worn. The
damage can be caused by excessive brake temperatures or physical contact with a pot
hole or curb. Sometimes the noise will vary when turning. Left hand turns increase the
load on the vehicle’s right side, and right turns load the left side. A failed front wheel
bearing may also cause a slight steering wheel vibration when turning. A bearing
which exhibits noise must be replaced.
b. Check the tire condition and balance. An internally damaged tire may cause failure
symptoms similar to failed suspension parts. For diagnostic purposes, try a known
good set of tires and replace defective tires.
4. Vehicle makes a squeaking noise over bumps
a. Check the vehicle’s ball joints for wear, damaged or leaking boots. Replace a ball joint
if it is loose, the boot is damaged and leaking, or the ball joint is binding. When re-
placing suspension parts, check the vehicle for alignment.
b. Check for seized or deteriorated bushings. Replace bushings that are worn or dam-
aged and check the vehicle for alignment.
c. Check for the presence of sway bar or stabilizer bar bushings which wrap around the
bar. Inspect the condition of the bushings and replace if worn or damaged. Remove
the bushing bracket and apply a thin layer of suspension grease to the area where the
bushings wrap around the bar and reinstall the bushing brackets. ~
5. Vehicle vibrates when driven
a. Check the road surface. Roads which have rough or uneven surfaces may cause un-
usual vi brations.
b. Check the tire condition and balance. An internally damaged tire may cause failure
symptoms similar to failed suspension parts. For diagnostic purposes, try a known
good set of tires and replace defective tires immediately.
c. Check for a worn Constant Velocity (CV-joint) joint, universal (U- joint) or flex joint
and replace if loose, damaged or binding.
d. Check for a loose, bent, or out-of-balance axle or drive shaft. Replace damaged or
failed components.
NOTE: Diagnosing failures related to wheels, tires, steering and the sus-
pension system can often times be accomplished with a careful and thor-
ough test drive. Bearing noises are isolated by noting whether the noises
or symptoms vary when turning left or right, or occur while driving a
straight line. During a teft hand turn, the vehicle’s weight shifts to the
right, placing more force on the right side bearings, such that if a right side
wheel bearing is worn or damaged, the noise or vibration should increase
during light-to-heavy acceleration. Conversely, on right hand turns, the ve-
hicle tends to lean to the left, loading the left side bearings.
Knocking noises in the suspension when the vehicle is driven over rough roads, rail-
road tracks and speed bumps indicate worn suspension components such as bushings,
ball joints or tie rod ends, or a worn steering system.
1. One headlight only works on high or low beam
a. Check for battery voltage at headlight electrical connector. If battery voltage is present,
replace the headlight assembly or bulb if available separately. If battery voltage is not
present, refer to the headlight wiring diagram to troubleshoot.
2. Headlight does not work on high or low beam
a. Check for battery voltage and ground at headlight electrical connector. If battery volt-
age is present, check the headlight connector ground terminal for a proper ground. If
battery voltage and ground are present at the headlight connector, replace the head-
light assembly or bulb if available separately. If battery voltage or ground is not pre-
sent, refer to the headlight wiring diagram to troubleshoot.
b. Check the headlight switch operation. Replace the switch if the switch is defective or
ooerates intermittentlv. 1. Tail light, running light or side marker light inoperative
a. Check for battery voltage and ground at light’s electrical connector. If battery voltage is
present, check the bulb socket and electrical connector ground terminal for a proper
ground. If battery voltage and ground are present at the light connector, but not in the
socket, clean the socket and the ground terminal connector. If battery voltage and
ground are present in the bulb socket, replace the bulb. If battery voltage or ground is
not present, refer to the wiring diagram to troubleshoot for an open circuit.
b. Check the light switch operation and replace if necessary.
2. Tall light, running light or side marker light works intermittently
a. Check the bulb for a damaged filament, and replace if damaged.
b. Check the bulb and bulb socket for corrosion, and clean or replace the bulb and
socket.
w 3. Headlight(s) very dim
a. Check for battery voltage and ground at headlight electrical connector. If battery volt-
age is present, trace the ground circuit for the headlamp electrical connector, then
clean and repair as necessary. If the voltage at the headlight electrical connector is
significantly less than the voltage at the battery, refer to the headlight wiring diagram
to troubleshoot and locate the voltage drop. c. Check for loose, damaged or corroded wires and electrical terminals, and repair as
necessary.
d. Check the light switch operation and replace if necessary.
3. Tail light, running light or side marker light very dim
a. Check the bulb and bulb socket for corrosion and clean or replace the bulb and
socket.
II-14 TROUBLESHOOTING
b. Check for low voltage at the bulb socket positive terminal or a poor ground. If voltage
is low, or the ground marginal, trace the wiring to, and check for loose, damaged or
corroded wires and electrical terminals; repair as necessary.
c. Check the light switch operation and replace if necessary.
1. Interior light inoperative
a. Verify the interior light switch location and position(s), and set the switch in the cor-
rect position.
b. Check for battery voltage and ground at the interior light bulb socket. If battery voltage
and ground are present, replace the bulb. If voltage is not present, check the interior
light fuse for battery voltage. If the fuse is missing, replace the fuse. If the fuse has
blown, or if battery voltage is present, refer to the wiring diagram to troubleshoot the
cause for an open or shorted circuit. If ground is not present, check the door switch
contacts and clean or repair as necessary.
2. Interior light works intermittent/y
a. Check the bulb for a damaged filament, and replace if damaged.
b. Check the bulb and bulb socket for corrosion, and clean or replace the bulb and
socket.
c. Check for loose, damaged or corroded wires and electrical terminals; repair as neces-
sary.
d. Check the door and light switch operation, and replace if necessary.
3. Interior light very dim
a. Check the bulb and bulb socket for corrosion, and clean or replace the bulb and
socket.
b. Check for low voltage at the bulb socket positive terminal or a poor ground. If voltage
is low, or the ground marginal, trace the wiring to, and check for loose, damaged or
corroded wires and electrical terminals; repair as necessary.
c. Check the door and light switch operation, and replace if necessary.
1. One brake light inoperative
a. PressPress the brake pedal and check for battery voltage and ground at the brake light
bulb socket. If present, replace the bulb. If either battery voltage or ground is not pre-
sent, refer to the wiring diagram to troubleshoot.
2. Both brake lights inoperative
a. Press the brake pedal and check for battery voltage and grou’nd at the brake light bulb
socket. If present, replace both bulbs. If battery voltage is not present, check the brake
light switch adjustment and adjust as necessary. If the brake light switch is properly
adjusted, and battery voltage or the ground is not present at the bulb sockets, or at the
bulb electrical connector with the brake pedal pressed, refer to the wiring diagram to
troubleshoot the cause of an open circuit.
3. One or both brake lights very dim
a. Press the brake pedal and measure the voltage at the brake light bulb socket. If the
measured voltage is close to the battery voltage, check for a poor ground caused by a
loose, damaged, or corroded wire, terminal, bulb or bulb socket. If the ground is
bolted to a painted surface, it may be necessary to remove the electrical connector and
clean the mounting surface, so the connector mounts on bare metal. If battery voltage
is low, check for a poor connection caused by either a faulty brake light switch, a
loose, damaged, or corroded wire, terminal or electrical connector. Refer to the wiring
diagram to troubleshoot the cause of a voltage drop.
1. Warning light(s) stay on when the engine is started
Ignition, Battery or Alternator Warning light a. Check the alternator output and voltage regulator operation, and replace as necessary.
b. Check the warning light wiring for a shorted wire.
Check Engine Light a. Check the engine for routine maintenance and tune-up status. Note the engine tune-up
specifications and verify the spark plug, air filter and engine oil condition; replace
and/or adjust items as necessary.
b. Check the fuel tank for low fuel level, causing an intermittent lean fuel mixtur
e. Top off fuel tank and reset check engine light.
c. Check for a failed or disconnected engine fuel or ignition component, sensor or con-
trol unit and repair or replace as necessary.
d. Check the intake manifold and vacuum hoses for air leaks and repair as
necessary.
e. Check the engine’s mechanical condition for excessive oil consumption.
Anti-Lock Braking System (ABS) Light a. Check the wheel sensors and sensor rings for debris, and clean as necessary.
b. Check the brake master cylinder for fluid leakage or seal failure and replace as neces-
sary.
c, Check the ABS control unit, pump and proportioning valves for proper operation; re-
place as necessary.
d. Check the sensor wiring at the wheel sensors and the ABS control unit for a loose or
shorted wire, and repair as necessary.
brake Warning Light a. Check the brake fluid level and check for possible leakage from the hydraulic lines and
seals. Top off brake fluid and repair leakage as necessary.
b. Check the brake linings for wear and replace as necessary.
c. Check for a loose or shot-ted brake warning light sensor or wire, and replace or repair
as necessary.
Oil Pressure Warning Light a. Stop the engine immediately. Check the engine oil level and oil filter condition, and
top off or change the oil as necessary.
b. Check the oil pressure sensor wire for being shorted to ground. Disconnect the wire
from the oil pressure sensor and with the ignition in the ON position, but not running,
the oil pressure light should not be working. If the light works with the wire discon-
nected, check the sensor wire for being shorted to ground. Check the wire routing to
make sure the wire is not pinched and check for insulation damage. Repair or replace
the wire as necessary and recheck before starting the engine.
c. Remove the oil pan and check for a clogged oil pick-up tube screen.
d. Check the oil pressure sensor operation by substituting a known good sensor.
e. Check the oil filter for internal restrictions or leaks, and replace as necessary.
WARNING: If the engine is operated with oil pressure below the manufac-
turer’s specification, severe (and costly) engine damage could occur. Low
oil pressure can be caused by excessive internal wear or damage to the en-
gine bearings, oil pressure relief valve, oil pump or oil pump drive mecha-
nism.
Before starting the engine, check for possible causes of rapid oil loss, such as leaking
oil lines or a loose, damaged, restricted, or leaking oil filter or oil pressure sensor. If the
engine oil level and condition are acceptable, measure the engine’s oil pressure using a
pressure gauge, or determine the cause for the oil pressure warning light to function
when the engine is running, before operating the engine for an extended period of time.
Another symptom of operating an engine with low oil pressure is the presence of severe
knocking and tapping noises.
Parking Brake Warning Light a. Check the brake release mechanism and verify the parking brake has been fully re-
leased.
b. CheckCheck the parking brake light switch for looseness or misalignment.
c. CheckCheck for a damaged switch or a loose or shorted brake light switch wire, and
replace or repair as necessary.
2. Warning light(s) flickers on and off when driving
Ignition, Battery or Alternator Warning Light a. Check the alternator output and voltage regulator operation. An intermittent condition
may indicate worn brushes, an internal short, or a defective voltage regulator. Replace
the alternator or failed component.
b. Check the warning light wiring for a shorted, pinched or damaged wire and repair as
necessary.
Check Engine Light a. Check the engine for required maintenance and tune-up status. Verify engine tune-up
specifications, as well as spark plug, air filter and engine oil condition; replace and/or
adjust items as necessary.
b. Check the fuel tank for low fuel level causing an intermittent lean fuel mixture. Top off
fuel tank and reset check engine light.
c. Check for an intermittent failure or partially disconnected engine fuel and ignition
component, sensor or control unit; repair or replace as necessary.
d. Check the intake manifold and vacuum hoses for air leaks, and repair as necessary.
e. Check the warning light wiring for a shorted, pinched or damaged wire and repair as
necessary.
Anti-Lock Braking System (ABS) Light a. Check the wheel sensors and sensor rings for debris, and clean as necessary.
b. Check the brake master cylinder for fluid leakage or seal failure and replace as neces-
sary.
c. Check the ABS control unit, pump and proportioning valves for proper operation, and
replace as necessary.