1900 MITSUBISHI DIAMANTE warning

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.

TROUBLESHOOTING 1145
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 Warninu Liaht a. Check the brakefluid~evel 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 shorted 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 check for a sudden and
rapid oil loss, such as a leaking oil line or oil pressure sensor, and repair or replace as
necessary.
b. Check the oil pressure sensor operation by substituting a known good sensor.
c. 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.
d. Remove the oil pan and check for a clogged oil pick-up tube screen.
Parking Brake Warning Light a. Check the brake release mechanism and verify the parking brake has been fully re-
leased.
b. Check the parking brake light switch for looseness or misalignment.
c. Check for a damaged switch or a loose or shorted brake light switch wire, and replace
or repair as necessary.
3. Warning li#ht(s) inoperative with iflnition on,
and engine not started
a. Check for a defective bulb by installing a known good bulb.
b. Check for a defective wire using the appropriate wiring diagram(s).
c. Check for a defective sending unit by removing and then grounding the wire at the
sending unit. If the light comes on with the ignition on when grounding the wire, re-
place the sending unit.
1. Turn siflnais or hazard iiflhts come on, but do not flash
a. Check for a defective flasher unit and replace as necessary.
2. Turn signals or hazard iiflhts do not function on either side
a. Check the fuse and replace, if defective.
b. Check the flasher unit by substituting a known good flasher unit.
c. Check the turn signal electrical system for a defective component, open circuit, short
circuit or poor ground.
3. Turn siflnais or hazard lights only work on one side
a. Check for failed bulbs and replace as necessary.
b. Check for poor grounds in both housings and repair as necessary.
4. One siflnai light does not work
a. Check for a failed bulb and replace as necessary.
b. Check for corrosion in the bulb socket, and clean and repair as necessary.
c. Check for a poor ground at the bulb socket, and clean and repair as necessary.
5. Turn signals flash too slowly
a. Check signal bulb(s) wattage and replace with lower wattage bulb(s). 6. Turn signals flash too fast
a, Check signal bulb(s) wattage and replace with higher wattage bulb(s).
b. Check for installation of the correct flasher unit and replace if incorrect.
7. Four-way hazard flasher indicator iiflhi inoperative
a. Verify that the exterior lights are functioning and, if so, replace indicator bulb.
b. Check the operation of the warning flasher switch and replace if defective.
0. Turn signal indicator ii#ht(s) do not work in either direction
a. Verify that the exterior lights are functioning and, if so, replace indicator bulb(s).
b. Check for a defective flasher unit by substituting a known good unit.
9. One turn signal indicator liflht does not work
a. Check for a defective bulb and replace as necessary.
b. Check for a defective flasher unit by substituting a known good unit.
1. Horn does not operate
a. Check for a defective fuse and replace as necessary.
b. Check for battery voltage and ground at horn electrical connections when pressing the
horn switch. If voltage is present, replace the horn assembly. If voltage or ground is
not present, refer to Chassis Electrical coverage for additional troubleshooting tech-
niques and circuit information.
2. Horn has an unusual tone
a. On single horn systems, replace the horn.
b. On dual horn systems, check the operation of the second horn. Dual horn systems
have a high and low pitched horn. Unplug one horn at a time and recheck operation.
Replace the horn which does not function.
c. Check for debris or condensation build-up in horn and verify the horn positioning. If
the horn has a single opening, adjust the opening downward to allow for adequate
drainage and to prevent debris build-up.
1. Windshield wipers do not operate
a. Check fuse and replace as necessary.
b. Check switch operation and repair or replace as necessary.
c. Check for corroded, loose, disconnected or broken wires and clean or repair as neces-
sary.
d. Check the ground circuit for the wiper switch or motor and repair as necessary.
2. Windshield wiper motor makes a humming noise, gets hot or blows
fuses
a. Wiper motor damaged internally; replace the wiper motor.
b. Wiper linkage bent, damaged or seized. Repair or replace wiper linkage as necessary.
3. Windshield wiper motor operates, but one or both wipers fail to move
a. Windshield wiper motor linkage loose or disconnected. Repair or replace linkage as
necessary.
b. Windshield wiper arms loose on wiper pivots. Secure wiper arm to pivot or replace
both the wiper arm and pivot assembly.
4. Windshield wipers will not park
a. Check the wiper switch operation and verify that the switch properly interrupts the
power supplied to the wiper motor.
b. If the wiper switch is functioning properly, the wiper motor parking circuit has failed.
Replace the wiper motor assembly. Operate the wiper motor at least one time before
installing the arms and blades to ensure correct positioning, then recheck using the
highest wiper speed on a wet windshield to make sure the arms and blades do not
contact the windshield trim.
1. Speedometer does not work to minimize sharp bends or kinks.
If the sheathing has been
damaged, replace the ca-
a. Check and verify that the speedometer cable is properly seated into the speedometer ble assembly.
assembly and the speedometer drive gear. b. Check the speedometer cable for adequate lubrication. Remove the cable, inspect for
b. Check the speedometer cable for breakage or rounded-off cable ends where the cable damage, clean, lubricate and reinstall. If the cable has been damaged, replace the ca-
seats into the speedometer drive gear and into the speedometer assembly. If damaged, ble.
broken or the cable ends are rounded off, replace the cable.
c. Check speedometer drive gear condition and replace as necessary. 3. Speedometer works intermittently
d. Install a known good speedometer to test for proper operation. If the substituted a. Check the cable and verify that the cable is fully installed and the fasteners are secure.
speedometer functions properly, replace the speedometer assembly. b. Check the cable ends for wear and rounding, and replace as necessary.

GLOSSARY 11-17
AIR/FUEL RATIO: The ratio of air-to-gasoline by weight in the fuel mixture
drawn into the engine.
AIR INJECTION: One method of reducing harmful exhaust emissions by in-
jecting air into each of the exhaust ports of an engine. The fresh air entering
the hot exhaust manifold causes any remaining fuel to be burned before it can
exit the tailpipe.
ALTERNATOR: A device which produces AC (alternating current) which is
converted to DC (direct current) to charge the car battery.
AMMETER: An instrument, calibrated in amperes, used to measure the flow
of an electrical current in a circuit. Ammeters are always connected in series
with the circuit being tested.
AMPERE: The rate of flow of electrical current present when one volt of elec-
trical pressure is applied against one ohm of electrical resistance.
ANALOG COMPUTER: Any microprocessor that uses similar (analogous)
electrical signals to make its calculations.
ARMATURE: A laminated, soft iron core wrapped by a wire that converts elec-
trical energy to mechanical energy as in a motor or relay. When rotated in
a magnetic field, it changes mechanical energy into electrical energy as in a
generator.
ATMOSPHERIC PRESSURE: The pressure on the Earth’s surface caused
by the weight of the air in the atmosphere. At sea level, this pressure is 14.7
psi at 32°F (101 kPa at OOC).
ATOMIZATION: The breaking down of a liquid into a fine mist that can be
suspended in air.
AXIAL PLAY: Movement parallel to a shaft or bearing bore.
BACKFIRE: The sudden combustion of gases in the intake or exhaust sys-
tem that results in a loud explosion.
BACKLASH: The clearance or play between two parts, such as meshed gears.
BACKPRESSURE: Restrictions in the exhaust system that slow the exit of
exhaust gases from the combustion chamber.
BAKELITE[reg]: A heat resistant, plastic insulator material commonly used
in printed circuit boards and transistorized components.
BALL BEARING: A bearingmade up of hardened inner and outer races be-
tween which hardened steel’balls roll.
BALLAST RESISTOR: A resistor in the primary ignition circuit that lowers
voltage after the engine is started to reduce wear on ignition components.
BEARING: A friction reducing, supportive device usually located between a
stationary part and a moving part.
BI-METAL TEMPERATURE SENSOR: Anv sensor or switch made of two
dissimilar types of metal that bend when heated or cooled due to the different
expansion rates of the alloys. These types of sensors usually function as an
on/off switch. BLOW-BY: Combustion gases, composed of water vapor and unburned fuel,
that leak past the piston rings into the crankcase during normal engine oper-
ation. These gases are removed by the PCV system to prevent the buildup of
harmful acids in the crankcase.
BRAKE PAD: A brake shoe and lining assembly used with disc brakes.
BRAKE SHOE: The backing for the brake lining. The term is, however, usu-
ally applied to the assembly of the brake backing and lining.
BUSHING: A liner, usually removable, for a bearing; an anti-friction liner used
in place of a bearing.
CALIPER: A hydraulically activated device in a disc brake system, which is
mounted straddling the brake rotor (disc). The caliper contains at least one
piston and two brake pads. Hydraulic pressure on the piston(s) forces the pads
against the rotor.
CAMSHAFT: A shaft in the engine on which are the lobes (cams) which op-
erate the valves. The camshaft is driven by the crankshaft, via a belt, chain or
gears, at one half the crankshaft speed.
CAPACITOR: A device which stores an electrical charge.
CARBON MONOXIDE (CO): A colorless, odorless gas given off as a nor-
mal byproduct of combustion. It is poisonous and extremely dangerous in con-
fined areas, building up slowly to toxic levels without warning if adequate ven-
tilation is not available.
CARBURETOR: A device, usually mounted on the intake manifold of an en-
gine, which mixes the air and fuel in the proper proportion to allow even com-
bustion
CATALYTIC CONVERTER: A device installed in the exhaust system, like a
muffler, that converts harmful byproducts of combustion into carbon dioxide
and water vapor by means of a heat-producing chemical reaction.
CENTRIFUGAL ADVANCE: A mechanical method of advancing the spark
timing by using flyweights in the distributor that react to centrifugal force gen-
erated by the distributor shaft rotation.
CHECK VALVE: Any one-way valve installed to permit the flow of air, fuel or
vacuum in one direction only.
CHOKE: The valve/plate that restricts the amount of air entering an engine on
the induction stroke, thereby enriching the air:fuel ratio.
CIRCUIT: Any unbroken path through which an electrical current can flow.
Also used to describe fuel flow in some instances.
CIRCUIT BREAKER: A switch which protects an electrical circuit from
overload by opening the circuit when the current flow exceeds a pre-
determined level. Some circuit breakers must be reset manually, while most
reset automatically.
COIL (IGNITION): Part of the ignition system that boosts the relatively low
voltage supplied by the car’s electrical system to the high voltage required to
fire the spark plugs.