Hard Wired Lamp Diagnosis; Anti-Lock Brake System Lamp - Jeep Cherokee 2000 Service Manual

8E - 6 INSTRUMENT PANEL SYSTEMS
DIAGNOSIS AND TESTING (Continued)
Successful completion of the actuator test will con-
firm that the instrument cluster is operational. How-
ever, there may still be a problem with the CCD data
bus, the Powertrain Control Module (PCM), the Air-
bag Control Module (ACM), the Sentry Key Immobi-
lizer Module (SKIM) or the inputs to one of these
electronic control modules. Use a DRB scan tool and
the proper Diagnostic Procedures manual for testing
of these components.
If an individual gauge does not respond properly,
or does not respond at all during the actuator test,
the instrument cluster should be removed. However,
check that the gauge mounting screws on the instru-
ment cluster electronic circuit board for proper tight-
ness before considering
replacement. If the gauge mounting screws check
OK, replace the faulty cluster.
If an individual indicator lamp does not illuminate
during the actuator test, the instrument cluster
should be removed. However, check that the incan-
descent lamp bulb is not faulty and that the bulb
holder is properly installed on the instrument cluster
electronic circuit board before considering instrument
cluster replacement. If the bulb and bulb holder
check OK, replace the faulty instrument cluster.
(1) Begin the test with the ignition switch in the
Off position.
(2) Depress the trip odometer reset button.
(3) While holding the trip odometer reset button
depressed, turn the ignition switch to the On posi-
tion, but do not start the engine.
(4) Release the trip odometer reset button.
(5) Compare the operation of the suspect gauge(s)
and/or indicator lamp(s) with the Instrument Cluster
Actuator Test chart (Fig. 1) or (Fig. 2).
(6) The instrument cluster will automatically exit
the self-diagnostic mode and return to normal opera-
tion at the completion of the test, if the ignition
switch is turned to the Off position during the test,
or if a vehicle speed message indicating that the
vehicle is moving is received from the PCM on the
CCD data bus during the test.
(7) Go back to Step 1 to repeat the test, if
required.

HARD WIRED LAMP DIAGNOSIS

Each of the lamps found in this section depends
upon a hard wired circuit input to the instrument
cluster for proper operation. The following procedures
will help to diagnose conditions that may cause an
inoperative hard wired lamp circuit condition.
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, REFER TO
RESTRAINT SYSTEMS BEFORE ATTEMPTING ANY
STEERING WHEEL,
INSTRUMENT PANEL COMPONENT DIAGNOSIS OR
instrument
GROUP 8M - PASSIVE
STEERING COLUMN,
SERVICE. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.

ANTI-LOCK BRAKE SYSTEM LAMP

The diagnosis found here addresses an inoperative
Anti-lock Brake System (ABS) lamp condition. If the
ABS lamp stays on with the ignition switch in the
On position, or comes on and stays on while driving,
refer to Antilock Brakes in the Diagnosis and Test-
ing section of Group 5 - Brakes for diagnosis. If no
ABS problem is found, the following procedure will
help locate a short or open in the ABS lamp circuit.
cluster
For complete circuit descriptions, refer to Instru-
ment Cluster in the Contents of Group 8W - Wiring
Diagrams.
(1) Check the fused ignition switch output (run/
start) fuse in the junction block. If OK, go to Step 2.
If not OK, repair the shorted circuit or component as
required and replace the faulty fuse.
(2) Turn the ignition switch to the On position.
Check for battery voltage at the fused ignition switch
output (run/start) fuse in the junction block. If OK,
go to Step 3. If not OK, repair the open fused ignition
switch output (run/start) circuit to the ignition switch
as required.
(3) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Remove the instrument cluster. Connect the battery
negative cable. Turn the ignition switch to the On
position and within five seconds check for continuity
between the ABS warning indicator driver circuit
cavity of the instrument cluster wire harness connec-
tor A and a good ground. There should be continuity
for five seconds after ignition On, and then an open
circuit. If OK, replace the faulty bulb. If not OK, go
to Step 4.
(4) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Disconnect the Controller Anti-lock Brake (CAB) wire
harness connector. Check for continuity between the
ABS warning indicator driver circuit cavity of the
instrument cluster wire harness connector A and a
good ground. There should be no continuity. If OK, go
to Step 5. If not OK, repair the shorted ABS warning
indicator driver circuit as required.
(5) Check for continuity between the ABS warning
indicator driver circuit cavities of the instrument
cluster wire harness connector A and the CAB wire
harness connector. There should be continuity. If OK,
refer to Antilock Brakes in the Diagnosis and Test-
ing section of Group 5 - Brakes for diagnosis of the
CAB. If not OK, repair the open ABS warning indi-
cator driver circuit as required.
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