Brake Warning Lamp; Check Gauges Lamp; Cluster Illumination Lamp; Cruise-On Indicator Lamp - Jeep 1997 Grand Cherokee Service Manual

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DIAGNOSIS AND TESTING (Continued)

BRAKE WARNING LAMP

The diagnosis found here addresses an inoperative
brake warning lamp condition. If the brake warning
lamp stays on with the ignition switch in the On
position and the parking brake released, or comes on
while driving, refer to Group 5 - Brakes for diagnosis.
If no service brake or parking brake problem is
found, proceed as follows. Refer to 8W-40 - Instru-
ment Cluster, 8W-35 - All-Wheel Anti-Lock Brakes,
and 8W-45 - Body Control Module in Group 8W -
Wiring Diagrams for circuit descriptions and dia-
grams.
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, REFER TO GROUP 8M - PASSIVE RESTRAINT
SYSTEMS BEFORE ATTEMPTING STEERING WHEEL,
STEERING COLUMN, OR INSTRUMENT PANEL COM-
PONENT DIAGNOSIS OR SERVICE. FAILURE TO
TAKE THE PROPER PRECAUTIONS COULD RESULT
IN ACCIDENTAL AIRBAG DEPLOYMENT AND POSSI-
BLE PERSONAL INJURY.
If the brake warning lamp fails to light during the
bulb test (for about four seconds after the ignition
switch is turned to the On position), replace the bulb
with a known good unit. If the lamp still fails to
light, diagnosis of the park brake switch and circuit,
the brake warning switch and circuit, the Body Con-
trol Module (BCM), the instrument cluster circuitry,
or the CCD data bus should be performed with a
DRB scan tool as described in the proper Body Diag-
nostic Procedures manual.

CHECK GAUGES LAMP

The diagnosis found here addresses an inoperative
lamp condition. If the check gauges lamp stays on
with the ignition switch in the On position, or comes
on while driving with no unusual gauge readings evi-
dent, refer to the proper Body Diagnostic Procedures
manual for diagnosis. For circuit descriptions and
diagrams, refer to 8W-30 - Fuel/Ignition Systems,
8W-40 - Instrument Cluster, and 8W-45 - Body Con-
trol Module in Group 8W - Wiring Diagrams.
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, REFER TO GROUP 8M - PASSIVE RESTRAINT
SYSTEMS BEFORE ATTEMPTING STEERING WHEEL,
STEERING COLUMN, OR INSTRUMENT PANEL COM-
PONENT DIAGNOSIS OR SERVICE. FAILURE TO
TAKE THE PROPER PRECAUTIONS COULD RESULT
IN ACCIDENTAL AIRBAG DEPLOYMENT AND POSSI-
BLE PERSONAL INJURY.
If the check gauges lamp fails to light during the
bulb test (about three seconds after the ignition
switch is turned to the On position), replace the
check gauges lamp bulb with a known good unit. If
INSTRUMENT PANEL SYSTEMS
the check gauges lamp still fails to operate, diagnosis
of the lamp, the instrument cluster circuitry, the
CCD data bus, and the Body Control Module (BCM)
should be performed with a DRB scan tool as
described in the proper Body Diagnostic Procedures
manual.

CLUSTER ILLUMINATION LAMP

The diagnosis found here addresses an inoperative
cluster illumination lamp condition. If the problem
being diagnosed is related to the dimming level of
the cluster illumination lamps, diagnosis should be
performed with a DRB scan tool as described in the
proper Body Diagnostic Procedures manual. For cir-
cuit descriptions and diagrams, refer to 8W-40 -
Instrument Cluster, 8W-45 - Body Control Module,
and/or 8W-50 - Front Lighting in Group 8W - Wiring
Diagrams.
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, REFER TO GROUP 8M - PASSIVE RESTRAINT
SYSTEMS BEFORE ATTEMPTING STEERING WHEEL,
STEERING COLUMN, OR INSTRUMENT PANEL COM-
PONENT DIAGNOSIS OR SERVICE. FAILURE TO
TAKE THE PROPER PRECAUTIONS COULD RESULT
IN ACCIDENTAL AIRBAG DEPLOYMENT AND POSSI-
BLE PERSONAL INJURY.
If only individual cluster illumination lamps are
inoperative, replace the faulty bulbs. If all of the
cluster illumination lamps are inoperative, proceed
as follows.
(1) Disconnect and isolate the battery negative
cable. Remove the cluster bezel and the cluster
assembly as described in this group.
(2) Connect the battery negative cable and turn
the park lamps on with the headlamp switch. Adjust
the panel lamp dimmer switch knob to its highest
level (fully upwards). Check for voltage at the panel
lamp driver circuit cavity of the cluster wire harness
connector. If OK, replace the faulty instrument clus-
ter. If not OK, go to Step 3.
(3) Disconnect and isolate the battery negative
cable. Unplug the white 24-way Body Control Module
(BCM) wire harness connector. Check for continuity
between the panel lamp driver circuit cavities of the
cluster wire harness connector and the BCM wire
harness connector. If OK, refer to Group 8L - Lamps
for diagnosis of the headlamp switch and/or the
proper Body Diagnostic Procedures manual for diag-
nosis of the BCM. If not OK, repair the open circuit
as required.

CRUISE-ON INDICATOR LAMP

The diagnosis found here addresses an inoperative
lamp condition. If the problem being diagnosed is an
inaccurate cruise-on indicator lamp, refer to Group
8E - 13