1995 JEEP YJ oil level

CAUTION: Do not operate the engine with a spark
plug shorted for more than a minute. The catalytic
converter may be damaged.
Isolate the compression leak by shorting each
spark plug to the cylinder block. The gauge pointer
should stop or decrease vibration when spark plug
for leaking cylinder is shorted. This happens because
of the absence of combustion pressure.
COMBUSTION LEAKAGE TEST (WITHOUT
PRESSURE TESTER)
DO NOT WASTE reusable coolant. If the solution
is clean, drain the coolant into a clean container for
reuse.
WARNING: DO NOT REMOVE THE CYLINDER
BLOCK DRAIN PLUGS OR LOOSEN THE RADIATOR
DRAINCOCK WITH THE SYSTEM HOT AND UNDER
PRESSURE. SERIOUS BURNS FROM COOLANT
CAN OCCUR.
Drain sufficient coolant to allow for thermostat re-
moval. Refer to Thermostat Replacement. Disconnect
the water pump drive belt.
Disconnect the upper radiator hose from the ther-
mostat housing. Remove the housing and thermostat.
Install the thermostat housing.
Add coolant to the radiator to bring the level to
within 6.3 mm (1/4 in) of the top of the thermostat
housing.
CAUTION: Avoid overheating. Do not operate the
engine for an excessive period of time. Open the
draincock immediately after the test to eliminate
boil over of coolant.
Start the engine and accelerate rapidly three times
(to approximately 3000 rpm) while observing the
coolant. If internal engine combustion gases are leak-
ing into the cooling system, bubbles will appear in
the coolant. If bubbles do not appear, there is no in-
ternal combustion gas leakage.
COOLANT RESERVE/OVERFLOW SYSTEM
The system works along with the radiator pressure
cap. This is done by using thermal expansion and
contraction of the coolant to keep the coolant free of
trapped air. It provides:
²A volume for coolant expansion and contraction.
²A convenient and safe method for checking/adjust-
ing coolant level at atmospheric pressure. This is
done without removing the radiator pressure cap.
²Some reserve coolant to the radiator to cover mi-
nor leaks and evaporation or boiling losses.
As the engine cools, a vacuum is formed in the
cooling system of both the radiator and engine. Cool-ant will then be drawn from the coolant tank and re-
turned to a proper level in the radiator.
The coolant reserve/overflow system consists of a
radiator mounted pressurized cap, a plastic reserve/
overflow tank (Figs. 22, 23 or 24), a tube (hose) con-
necting the radiator and tank, and an overflow tube
on the side of the tank.
Fig. 22 Reserve/Overflow TankÐYJ Models
Fig. 23 Reserve/Overflow TankÐXJ ModelsÐExcept
Right Hand Drive
7 - 24 COOLING SYSTEM SERVICE PROCEDURESJ

VISCOUS FAN DRIVE
DESCRIPTION AND OPERATION
Also refer to the previous section on Cooling Sys-
tem Fans.
The thermal viscous fan drive (Fig. 38 or 39) is a
silicone-fluid-filled coupling used to connect the fan
blades to either the engine or the water pump shaft.
The coupling allows the fan to be driven in a normal
manner. This is done at low engine speeds while lim-
iting the top speed of the fan to a predetermined
maximum level at higher engine speeds.
A thermostatic bimetallic spring coil is located on
the front face of the viscous fan drive unit (a typical
viscous unit is shown in figure 40). This spring coil
reacts to the temperature of the radiator discharge
air. It engages the viscous fan drive for higher fan
speed if the air temperature from the radiator rises
above a certain point. Until additional engine cooling
is necessary, the fan will remain at a reduced rpm re-
gardless of engine speed.
Only when sufficient heat is present, will the vis-
cous fan drive engage. This is when the air flowing
through the radiator core causes a reaction to the bi-
metallic coil. It then increases fan speed to provide
the necessary additional engine cooling.
Once the engine has cooled, the radiator discharge
temperature will drop. The bimetallic coil again re-
acts and the fan speed is reduced to the previous dis-
engaged speed.
CAUTION: Engines equipped with serpentine drive
belts have reverse rotating fans and viscous fan
drives. They are marked with the word REVERSE to
designate their usage. Installation of the wrong fan
or viscous fan drive can result in engine overheat-
ing.CAUTION: If the viscous fan drive is replaced be-
cause of mechanical damage, the cooling fan
blades should also be inspected. Inspect for fatigue
cracks, loose blades, or loose rivets that could
have resulted from excessive vibration. Replace fan
blade assembly if any of these conditions are
found. Also inspect water pump bearing and shaft
assembly for any related damage due to a viscous
fan drive malfunction.
NOISE
It is normal for fan noise to be louder (roar-
ing) when:
²The underhood temperature is above the engage-
ment point for the viscous drive coupling. This may
occur when ambient (outside air temperature) is very
high.
²Engine loads and temperatures are high such as
when towing a trailer.
²Cool silicone fluid within the fan drive unit is be-
ing redistributed back to its normal disengaged
(warm) position. This can occur during the first 15
seconds to one minute after engine start-up on a cold
engine.
LEAKS
Viscous fan drive operation is not affected by small
oil stains near the drive bearing. If leakage appears
excessive, replace the fan drive unit.
TESTING
If the fan assembly free-wheels without drag (the
fan blades will revolve more than five turns when
spun by hand), replace the fan drive. This spin test
must be performed when the engine is cool.
For the following test, the cooling system must be
in good condition. It also will ensure against exces-
sively high coolant temperature.
WARNING: BE SURE THAT THERE IS ADEQUATE
FAN BLADE CLEARANCE BEFORE DRILLING.
(1) Drill a 3.18-mm (1/8-in) diameter hole in the
top center of the fan shroud.
(2) Obtain a dial thermometer with an 8 inch stem
(or equivalent). It should have a range of -18É-to-
105ÉC (0É-to-220É F). Insert thermometer through the
hole in the shroud. Be sure that there is adequate
clearance from the fan blades.
(3) Connect a tachometer and an engine ignition
timing light (timing light is to be used as a strobe
light).
(4) Block the air flow through the radiator. Secure
a sheet of plastic in front of the radiator (or air con-
ditioner condenser). Use tape at the top to secure the
plastic and be sure that the air flow is blocked.
Fig. 40 Typical Viscous Fan Drive
7 - 34 COOLING SYSTEM SERVICE PROCEDURESJ

The high-line cluster includes the following gauges:
²coolant temperature gauge
²fuel gauge
²oil pressure gauge
²speedometer/odometer
²tachometer
²trip odometer
²voltmeter.
The high-line cluster includes provisions for the fol-
lowing indicator lamps:
²anti-lock brake system lamp
²brake warning lamp
²four-wheel drive indicator lamps
²headlamp high beam indicator lamp
²low fuel warning lamp
²low washer fluid warning lamp
²malfunction indicator (Check Engine) lamp
²seat belt reminder lamp
²turn signal indicator lamps
²upshift indicator lamp.
GAUGES
With the ignition switch in the ON or START posi-
tion, voltage is supplied to all gauges through the in-
strument cluster gauge area printed circuit. With the
ignition switch in the OFF position, voltage is not
supplied to the gauges. A gauge pointer may remain
within the gauge scale after the ignition switch is
OFF. However, the gauges do not accurately indicate
any vehicle condition unless the ignition switch is
ON.
All gauges except the odometer are air core mag-
netic units. Two fixed electromagnetic coils are lo-
cated within the gauge. These coils are wrapped at
right angles to each other around a movable perma-
nent magnet. The movable magnet is suspended
within the coils on one end of a shaft. The gauge nee-
dle is attached to the other end of the shaft.
One of the coils has a fixed current flowing through
it to maintain a constant magnetic field strength.
Current flow through the second coil changes, which
causes changes in its magnetic field strength. The
current flowing through the second coil can be
changed by:
²a variable resistor-type sending unit (fuel level,
coolant temperature, or oil pressure)
²changes in electrical system voltage (voltmeter)
²electronic control circuitry (speedometer/odometer,
tachometer).
The gauge needle moves as the movable permanent
magnet aligns itself to the changing magnetic fields
created around it by the electromagnets.
COOLANT TEMPERATURE GAUGE
The coolant temperature gauge gives an indication
of engine coolant temperature. The coolant tempera-
ture sending unit is a thermistor that changes elec-
trical resistance with changes in engine coolanttemperature. High sending unit resistance causes
low coolant temperature readings. Low resistance
causes high coolant temperature readings.
The gauge will read at the high end of the scale
when the ignition switch is turned to the START po-
sition. This is caused by the bulb test circuit wiring
provision. The same wiring is used for the high-line
cluster with a coolant temperature gauge and the
low-line cluster with a coolant temperature warning
lamp. Sending unit resistance values are shown in a
chart in Specifications.
FUEL GAUGE
The fuel gauge gives an indication of the level of
fuel in the fuel tank. The fuel gauge sending unit has
a float attached to a swing-arm in the fuel tank. The
float moves up or down within the fuel tank as fuel
level changes. As the float moves, an electrical con-
tact on the swing-arm wipes across a resistor coil,
which changes sending unit resistance. High sending
unit resistance causes low fuel level readings. Low
resistance causes high fuel level readings. Sending
unit resistance values are shown in a chart in Spec-
ifications.
OIL PRESSURE GAUGE
The oil pressure gauge gives an indication of en-
gine oil pressure. The combination oil pressure send-
ing unit contains a flexible diaphragm. The
diaphragm moves in response to changes in engine
oil pressure. As the diaphragm moves, sending unit
resistance increases or decreases. High resistance on
the gauge side of the sending unit causes high oil
pressure readings. Low resistance causes low oil
pressure readings. Sending unit resistance values are
shown in a chart in Specifications.
SPEEDOMETER/ODOMETER
The speedometer/odometer gives an indication of
vehicle speed and travel distance. The speedometer
receives a vehicle speed pulse signal from the Vehicle
Speed Sensor (VSS). An electronic integrated circuit
contained within the speedometer reads and analyzes
the pulse signal. It then adjusts the ground path re-
sistance of one electromagnet in the gauge to control
needle movement. It also sends signals to an electric
stepper motor to control movement of the odometer
number rolls. Frequency values for the pulse signal
are shown in a chart in Specifications.
The VSS is mounted to an adapter near the trans-
mission (two-wheel drive) or transfer case (four-wheel
drive) output shaft. The sensor is driven through the
adapter by a speedometer pinion gear. The adapter
and pinion vary with transmission, transfer case,
axle ratio and tire size. Refer to Group 21 - Trans-
mission and Transfer Case for more information.
8E - 2 INSTRUMENT PANEL AND GAUGESÐXJJ

HEADLAMP HIGH BEAM INDICATOR LAMP
The high beam indicator lamp is controlled by the
headlamp dimmer (multi-function) switch. One side
of the indicator bulb is grounded at all times. The
other side of the bulb receives battery feed through
the contacts of the dimmer switch when the multi-
function switch stalk is actuated to turn the head-
lamp high beams on. Refer to Group 8L - Lamps for
more information.
LOW FUEL WARNING LAMP
A Light-Emitting Diode (LED) on the face of the
fuel gauge will light when the fuel level falls below
approximately 4 gallons. A low fuel warning module
attached to the rear of the fuel gauge controls when
the LED will light. When the module senses 66.5
ohms or more resistance from the fuel level sending
unit for 10 continuous seconds, the LED will light.
When the module senses 63.5 ohms or less resistance
from the fuel level sending unit for 20 continuous
seconds, the LED is turned off.
LOW OIL PRESSURE WARNING LAMP
The low oil pressure warning lamp lights with the
ignition switch in the ON position and the engine not
running. The lamp should be off when the engine is
running. Battery voltage is supplied to one side of
the indicator bulb when the ignition switch is turned
ON. The warning lamp side of the combination oil
pressure sending unit is connected to the other side
of the bulb. When normal engine oil pressure is ap-
plied to the sending unit, resistance on the warning
lamp side is high and the lamp goes off. When engine
oil pressure is too low, resistance on the warning
lamp side of the sending unit is low, which causes
the bulb to light.
LOW WASHER FLUID WARNING LAMP
The low washer fluid warning lamp indicates when
the fluid level in the washer reservoir is too low. The
washer fluid level sensor uses a float in the reservoir
to monitor fluid level. The action of the float opens or
closes the switch within the sensor that provides ig-
nition-switched battery voltage to the lamp bulb. Re-
fer to Group 8K - Wiper and Washer Systems for
more information.
MALFUNCTION INDICATOR LAMP
The CHECK ENGINE or Malfunction Indicator
Lamp (MIL) lights each time the ignition switch is
turned ON, and stays on for 3 seconds as a bulb test.
If the Powertrain Control Module (PCM) receives an
incorrect signal or no signal from certain fuel oremission system related circuits or components, the
lamp is turned on. This will indicate that the PCM
has recorded a Diagnostic Trouble Code (DTC) in
electronic memory for a circuit or component mal-
function. Refer to Group 14 - Fuel System for more
information.
SEAT BELT REMINDER LAMP
The seat belt reminder lamp lights for 4 to 8 sec-
onds after the ignition switch is turned to the ON po-
sition. A timer in the chime/buzzer module controls
ignition-switched battery feed to the lamp. Refer to
Group 8U - Chime/Buzzer Warning Systems for more
information.
TURN SIGNAL INDICATOR LAMPS
The left and right turn signal indicator lamps are
controlled by the turn signal and hazard warning
(multi-function) switches. One side of the bulb for
each lamp is grounded at all times. The other side of
the bulb receives battery feed through the contacts of
the multi-function switch when the turn signal lever
(multi-function switch stalk) or hazard warning but-
ton are actuated. Refer to Group 8J - Turn Signal
and Hazard Warning Systems for more information.
UPSHIFT INDICATOR LAMP
Vehicles equipped with manual transmissions have
an optional upshift indicator lamp. Ground feed for
the lamp is switched by the Powertrain Control Mod-
ule (PCM). The lamp lights to indicate when the
driver should shift to the next highest gear for best
fuel economy. The PCM will turn the lamp off after 3
to 5 seconds if the upshift is not performed. The lamp
will remain off until the vehicle stops accelerating
and is brought back to the range of lamp operation,
or until the transmission is shifted into another gear.
The indicator lamp is normally on when the igni-
tion switch is turned ON and is turned off when the
engine is started. The lamp will be turned on during
vehicle operation according to engine speed and load.
CLUSTER ILLUMINATION LAMPS
All cluster illumination lamps receive battery feed
from the instrument lamps fuse in the fuseblock
module through the panel dimmer rheostat of the
headlamp switch. When the park or headlamps are
on, the cluster illumination lamps light. Illumination
brightness can be adjusted by rotating the headlamp
switch knob (clockwise to dim, counterclockwise to
brighten).
8E - 4 INSTRUMENT PANEL AND GAUGESÐXJJ

(2) Disconnect battery negative cable. Remove in-
strument cluster bezel and cluster assembly. Unplug
cluster connector A. Connect battery negative cable.
Turn headlamps on and select high beam. Check for
battery voltage at cavity A4 of cluster connector A. If
OK, replace indicator bulb. If not OK, repair circuit
to headlamp dimmer (multi-function) switch as re-
quired.
LOW FUEL WARNING LAMP
(1) Check that fuel gauge is operating as designed.
See Fuel Gauge Calibration chart in Specifications. If
OK, go to next step. If not OK, see Fuel Gauge in
this section for diagnosis.
(2) With at least 10 gallons of fuel in fuel tank, un-
plug fuel tank sending unit connector. Turn ignition
switch to ON and wait 10 seconds. Lamp (LED)
should light. Reconnect fuel tank sending unit and
wait 20 seconds. Lamp (LED) should go off. If not
OK, replace low fuel warning lamp module.
LOW OIL PRESSURE WARNING LAMP
The diagnosis found here addresses an inoperative
lamp condition. If the problem being diagnosed is re-
lated to lamp accuracy, be certain to confirm that
problem is with lamp and not with engine oiling sys-
tem. Actual engine oil pressure should be checked
with a test gauge before you proceed with lamp diag-
nosis. Refer to Group 9 - Engines for more informa-
tion.
(1) Turn ignition switch to ON. Lamp should light.
Start engine. Lamp should go off. If not OK, turn en-
gine off and go to next step.
(2) Unplug connector at oil pressure switch (Fig.
3). The switch is located on right side of engine block.
On 2.5L engine, it is just forward of ignition distrib-
utor and just to the rear of generator mounting
bracket. On 4.0L engine, it is just to the rear of igni-
tion distributor and above oil filter adapter. Install a
jumper wire from connector to a good ground. Turn
ignition switch to ON. Lamp should light. Unplug
jumper wire. Lamp should go out. If OK, replace oil
pressure switch. If not OK, go to next step.
(3) Turn ignition switch to OFF. Disconnect battery
negative cable. Remove instrument cluster bezel and
cluster assembly. Install a jumper wire from cavity
B7 (cavity B8 - RHD) of cluster connector A to a good
ground. Connect battery negative cable and turn ig-
nition switch to ON. Lamp should light. If OK, go to
next step. If not OK, replace lamp bulb.
(4) Turn ignition switch to OFF. Disconnect battery
negative cable. Unplug instrument cluster connector
A. Check continuity between cavity B7 (cavity B8 -
RHD) of cluster connector A and a good ground.
There should be no continuity. If OK, go to next step.
If not OK, repair short circuit as required.
(5) Check continuity between cavity B7 (cavity B8
- RHD) of cluster connector A and oil pressure switchconnector. There should be continuity. If not OK, re-
pair open circuit as required.
LOW WASHER FLUID WARNING LAMP
(1) Unplug washer fluid level switch connector.
Turn ignition switch to ON. Check for battery voltage
at connector cavity A. If OK, turn ignition switch to
OFF and go to next step. If not OK, repair open cir-
cuit to fuse F6 in PDC.
(2) Install a jumper wire from cavity A to cavity B
of washer fluid level switch connector. Turn ignition
switch to ON. Lamp should light. Unplug jumper and
lamp should go OFF. If OK, replace washer fluid
level switch. If not OK, go to next step.
(3) Turn ignition switch to OFF. Disconnect battery
negative cable. Remove instrument cluster bezel and
cluster assembly. Unplug instrument cluster (tell-
tale) connector B. Check continuity between cavity 16
(cavity 1 - RHD) of cluster connector B and a good
ground. There should be continuity. If OK, plug clus-
ter connector B back into cluster and go to next step.
If not OK, repair open circuit to ground as required.
(4) Connect battery negative cable. Install a
jumper wire from a 12-volt battery feed to cavity 1
(cavity 16 - RHD) of cluster connector B. Lamp
should light. If OK, go to next step. If not OK, re-
place bulb.
(5) Disconnect battery negative cable. Unplug clus-
ter connector B. Check continuity between cavity 1
(cavity 16 - RHD) of cluster connector B and a good
ground. There should be no continuity. If OK, go to
next step. If not OK, repair short circuit to switch as
required.
(6) Check continuity between cavity 1 (cavity 16 -
RHD) of cluster connector B and cavity B of washer
fluid level switch connector. There should be continu-
ity. If not OK, repair open circuit to switch as re-
quired.
MALFUNCTION INDICATOR LAMP
The diagnosis found here addresses an inoperative
lamp condition. If the lamp comes on and stays on
with engine running, refer to Group 14 - Fuel System
for diagnosis. If no fuel or emission system problem
is found, the following procedure will help locate a
short or open in the lamp circuit.
(1) Disconnect battery negative cable. Unplug PCM
connector. Install a jumper wire from cavity 32 of
PCM connector (Fig. 5) to a good ground. Connect
battery negative cable. Turn ignition switch to ON.
Lamp should light. Remove jumper wire and lamp
should go OFF. If OK, refer to Powertrain Diagnostic
Procedures to check PCM. If not OK, go to next step.
(2) Turn ignition switch to OFF. Disconnect battery
negative cable. Remove instrument cluster bezel and
cluster assembly. Install a jumper wire from cavity 2
(cavity 15 - RHD) of cluster (tell-tale) connector B to
a good ground. Connect battery negative cable. Turn
8E - 14 INSTRUMENT PANEL AND GAUGESÐXJJ

INSTRUMENT PANEL AND GAUGESÐYJ
CONTENTS
page page
INSTRUMENT PANEL AND GAUGESÐYJ..... 22
DIAGNOSIS............................ 23
GENERAL INFORMATION................. 20SERVICE PROCEDURES.................. 31
SPECIFICATIONS........................ 39
GENERAL INFORMATION
Following are general descriptions of major instru-
ment panel components. Refer to Group 8W - Wiring
Diagrams for complete circuit descriptions and dia-
grams.
INSTRUMENT PANEL
Modular instrument panel construction allows all
gauges and controls to be serviced from the front of
the panel. In addition, most instrument panel wiring
and heater components can be accessed without com-
plete instrument panel removal.
Removal of the left instrument cluster bezel allows
access to the main cluster assembly and most
switches. Removal of the center cluster bezel allows
access to the gauge package cluster assembly, the
heater controls, and the radio. Removal of the cluster
assemblies allows access to the individual gauges, il-
lumination and indicator lamp bulbs, printed cir-
cuits, and most wiring.
INSTRUMENT CLUSTERS
The instrument cluster used on YJ (Wrangler) mod-
els consists of two separate assemblies. The main
cluster assembly is located on the left side of the in-
strument panel, centered over the steering column
opening. The gauge package cluster assembly is lo-
cated near the center of the instrument panel. Each
cluster assembly is served by a separate printed cir-
cuit and wiring connector. Some variations of each
cluster exist due to optional equipment and regula-
tory requirements.
The main cluster assembly includes a speedometer/
odometer/trip odometer and a tachometer. It also in-
cludes provisions for the following indicator lamps:
²anti-lock brake system lamp
²brake warning lamp
²headlamp high beam indicator lamp
²malfunction indicator (Check Engine) lamp
²seat belt reminder lamp²turn signal indicator lamps
²upshift indicator lamp.
The gauge package cluster assembly includes a
four-wheel drive indicator lamp and the following
gauges:
²coolant temperature gauge
²fuel gauge
²oil pressure gauge
²voltmeter.
GAUGES
With the ignition switch in the ON or START posi-
tion, voltage is supplied to all gauges through the
two cluster printed circuits. With the ignition switch
in the OFF position, voltage is not supplied to the
gauges. A gauge pointer may remain within the
gauge scale after the ignition switch is OFF. How-
ever, the gauges do not accurately indicate any vehi-
cle condition unless the ignition switch is ON.
All gauges except the odometer are air core mag-
netic units. Two fixed electromagnetic coils are lo-
cated within the gauge. These coils are wrapped at
right angles to each other around a movable perma-
nent magnet. The movable magnet is suspended
within the coils on one end of a shaft. The gauge nee-
dle is attached to the other end of the shaft.
One of the coils has a fixed current flowing through
it to maintain a constant magnetic field strength.
Current flow through the second coil changes, which
causes changes in its magnetic field strength. The
current flowing through the second coil can be
changed by:
²a variable resistor-type sending unit (fuel level,
coolant temperature, or oil pressure)
²changes in electrical system voltage (voltmeter)
²electronic control circuitry (speedometer/odometer,
tachometer).
8E - 24 INSTRUMENT PANEL AND GAUGESÐYJJ

The gauge needle moves as the movable permanent
magnet aligns itself to the changing magnetic fields
created around it by the electromagnets.
COOLANT TEMPERATURE GAUGE
The coolant temperature gauge gives an indication
of engine coolant temperature. The coolant tempera-
ture sending unit is a thermistor that changes elec-
trical resistance with changes in engine coolant
temperature. High sending unit resistance causes
low coolant temperature readings. Low resistance
causes high coolant temperature readings. Sending
unit resistance values are shown in a chart in Spec-
ifications.
FUEL GAUGE
The fuel gauge gives an indication of the level of
fuel in the fuel tank. The fuel gauge sending unit has
a float attached to a swing-arm in the fuel tank. The
float moves up or down within the fuel tank as fuel
level changes. As the float moves, an electrical con-
tact on the swing-arm wipes across a resistor coil,
which changes sending unit resistance. High sending
unit resistance causes high fuel level readings. Low
resistance causes low fuel level readings. Sending
unit resistance values are shown in a chart in Spec-
ifications.
OIL PRESSURE GAUGE
The oil pressure gauge gives an indication of en-
gine oil pressure. The combination oil pressure send-
ing unit contains a flexible diaphragm. The
diaphragm moves in response to changes in engine
oil pressure. As the diaphragm moves, sending unit
resistance increases or decreases. High resistance on
the gauge side of the sending unit causes high oil
pressure readings. Low resistance causes low oil
pressure readings. Sending unit resistance values are
shown in a chart in Specifications.
SPEEDOMETER/ODOMETER
The speedometer/odometer give an indication of ve-
hicle speed and travel distance. The speedometer re-
ceives a vehicle speed pulse signal from the Vehicle
Speed Sensor (VSS). An electronic integrated circuit
contained within the speedometer reads and analyzes
the pulse signal. It then adjusts the ground path re-
sistance of one electromagnet in the gauge to control
needle movement. It also sends signals to an electric
stepper motor to control movement of the odometer
number rolls. Frequency values for the pulse signal
are shown in a chart in Specifications.
The VSS is mounted to an adapter near the trans-
fer case output shaft. The sensor is driven through
the adapter by a speedometer pinion gear. The
adapter and pinion vary with transmission, axle ratio
and tire size. Refer to Group 21 - Transmission and
Transfer Case for more information.
TACHOMETER
The tachometer gives an indication of engine speed
in Revolutions-Per-Minute (RPM). With the engine
running, the tachometer receives an engine speed
pulse signal from the Powertrain Control Module
(PCM). An electronic integrated circuit contained
within the tachometer reads and analyzes the pulse
signal. It then adjusts the ground path resistance of
one electromagnet in the gauge to control needle
movement. Frequency values for the pulse signal are
shown in a chart in Specifications.
TRIP ODOMETER
The trip odometer is driven by the same electronic
integrated circuit as the speedometer/odometer. How-
ever, by depressing the trip odometer reset knob on
the face of the speedometer, the trip odometer can be
reset to zero. The trip odometer is serviced only as a
part of the speedometer/odometer gauge assembly.
VOLTMETER
The voltmeter is connected in parallel with the bat-
tery. With the ignition switch ON, the voltmeter in-
dicates battery or generator output voltage,
whichever is greater.
INDICATOR LAMPS
All indicator lamps, except the four-wheel drive in-
dicator, are located in the main cluster tell-tale area
above the steering column opening. Each of the
lamps is served by the main cluster printed circuit
and cluster connector. The four-wheel drive indicator
lamp is located in the gauge package cluster and is
served by the gauge package printed circuit and clus-
ter connector.
Up to eleven indicator lamps can be found in the
tell-tale area of the main cluster. These lamps are ar-
ranged in two rows, with six lamps in the upper row
and five lamps in the lower row.
ANTI-LOCK BRAKE SYSTEM LAMP
The Anti-Lock Brake System (ABS) lamp is
switched to ground by the ABS module. The module
lights the lamp when the ignition switch is turned to
the START position as a bulb test. The lamp will
stay on for 3 to 5 seconds after vehicle start-up to in-
dicate a system self-test is in process. If the lamp re-
mains on after start-up, or comes on and stays on
while driving, it may indicate that the ABS module
has detected a system malfunction or that the system
has become inoperative. Refer to Group 5 - Brakes
for more information.
BRAKE WARNING LAMP
The brake warning lamp warns the driver that the
parking brake is applied or that the pressures in the
two halves of the split brake hydraulic system are
unequal. With the ignition switch turned ON, battery
JINSTRUMENT PANEL AND GAUGESÐYJ 8E - 25

HEADLAMP/FOG LAMP ADJUSTMENT USING
ALIGNMENT SCREENÐYJ
ALIGNMENT SCREEN PREPARATION
(1) Position vehicle on a level surface perpendicu-
lar to a flat wall 7.62 meters (25 ft) away from front
of headlamp lens (Fig. 1).
(2) If necessary, tape a line on the floor 7.62
meters (25 ft) away from and parallel to the wall.
(3) Measure from the floor up 1.27 meters (5 ft)
and tape a line on the wall at the centerline of the
vehicle. Sight along the centerline of the vehicle
(from rear of vehicle forward) to verify accuracy of
the line placement.
(4) Rock vehicle side-to-side three times to allow
suspension to stabilize.
(5) Jounce front suspension three times by pushing
downward on front bumper and releasing.
(6) Measure the distance from the center of head-
lamp lens to the floor. Transfer measurement to the
alignment screen (with tape). Use this line for up/
down adjustment reference.
(7) Measure distance from the centerline of the ve-
hicle to the center of each headlamp being aligned.
Transfer measurements to screen (with tape) to each
side of vehicle centerline. Use these lines for left/
right adjustment reference.
ADJUSTMENT
(1) Remove screws and both headlamp bezels.
(2) Clean front of the headlamps.
(3) Place headlamps on LOW beam.
(4) Cover front of the headlamp that is not being
adjusted.
(5) Turn vertical adjustment screw (Fig. 2) until
the headlamp beam pattern on screen/wall is similar
to the pattern depicted in Figure 1.
When using a headlamp aiming screen:
²Adjust the headlamps so that the beam horizontal
position is at 0.
²Adjust the beam vertical position is 25 mm (1 in)
downward from the lamp horizontal centerline.
(6) Rotate the horizontal adjustment screw until
the headlamp beam pattern on the aiming screen/
wall similar to the pattern in Figure 1.
(7) Cover front of the headlamp that has been ad-
justed and adjust the other headlamp beam as in-
structed above.
(8) Install headlamp bezels. Tighten the screws se-
curely.
FOG LAMP ADJUSTMENT
Prepare an alignment screen. Refer to Alignment
Screen Preparation paragraph in this section. A prop-
erly aligned fog lamp will project a pattern on the
alignment screen 100 mm (4 in.) below the fog lamp
centerline and straight ahead (Fig. 3)
HEADLAMP BULB REPLACEMENTÐYJ
(1) Remove the screws and the headlamp bezel
(Fig. 4).
(2) Remove the screws and headlamp bulb retain-
ing ring.
(3) Disconnect the headlamp bulb wire harness
connector and remove the bulb from the bucket.
INSTALLATION
(1) Position the bulb in the bucket and connect the
wire harness connector.
(2) Position retaining ring on the headlamp bulb
and install screws.
(3) Install the headlamp bezel. Tighten the screws
securely.
FOG LAMPSÐYJ
Fog lamps are turned OFF by the circuit relay
when the high beam driving lamps are turned ON.
Fog lamps may be operated ONLY when low beam
headlamps are ON. If the headlamps are switched to
high beam, the low beam lamps and fog lamps will
turn OFF. The fog lamps will go back on when the
high beams are switched OFF.
The indicator lamp on the fog lamp switch will go:
²OFF when the high beams lamps are switched
ON.
²ON when the high beam lamps are switched OFF.
FOG LAMP BULB REPLACEMENT
CAUTION: Do not touch the bulb glass with fingers
or other oily surfaces. Reduced bulb life will result.
(1) Remove the screws that attach the stone shield
and the reflector to the lamp housing. Remove the
stone shield and reflector from the lamp housing
(Fig. 5).
(2) Remove the bulb/element holder from the lens/
reflector.
Fig. 2 Headlamp Beam Adjustment Screws
JLAMPSÐYJ VEHICLES 8L - 23