Low Fuel Warning Lamp; Malfunction Indicator Lamp; Master Lighting Indicator Lamp - Jeep 1997 Grand Cherokee Service Manual

8E - 16 INSTRUMENT PANEL SYSTEMS
DIAGNOSIS AND TESTING (Continued)

LOW FUEL WARNING LAMP

The diagnosis found here addresses an inoperative
low fuel warning lamp condition. If the problem
being diagnosed is related to lamp accuracy, be cer-
tain to confirm the problem is the with the low fuel
warning lamp and not with the fuel gauge circuit.
See the diagnosis for the Fuel Gauge in this group. If
no fuel gauge problem is found, the following proce-
dure will help to identify a faulty low fuel warning
lamp circuit. For circuit descriptions and diagrams,
refer to 8W-40 - Instrument Cluster in Group 8W -
Wiring Diagrams.
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, REFER TO
RESTRAINT SYSTEMS
STEERING WHEEL,
INSTRUMENT PANEL COMPONENT DIAGNOSIS OR
SERVICE. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
If the low fuel warning lamp fails to light during
the bulb test (about four seconds after the ignition
switch is turned to the On position), replace the low
fuel warning lamp bulb with a known good unit. If
the indicator lamp still fails to operate, diagnosis of
the lamp, the instrument cluster circuitry, the CCD
data bus, or the Body Control Module (BCM) should
be performed with a DRB scan tool as described in
the proper Body Diagnostic Procedures manual.
Diagnosis of the fuel gauge sending unit and circuit
or the Powertrain Control Module (PCM) should be
performed with a DRB scan tool as described in the
proper Powertrain Diagnostic Procedures manual.

MALFUNCTION INDICATOR LAMP

The diagnosis found here addresses an inoperative
malfunction indicator (Check Engine) lamp condition.
If the lamp comes on and stays on with the engine
running, refer to Group 14 - Fuel Systems for diag-
nosis. For circuit descriptions and diagrams, refer to
8W-40 - Instrument Cluster in Group 8W - Wiring
Diagrams.
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, REFER TO
RESTRAINT SYSTEMS
STEERING WHEEL,
INSTRUMENT PANEL COMPONENT DIAGNOSIS OR
SERVICE. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
GROUP 8M - PASSIVE
BEFORE ATTEMPTING
STEERING COLUMN,
GROUP 8M - PASSIVE
BEFORE ATTEMPTING
STEERING COLUMN,
If the malfunction indicator lamp fails to light dur-
ing the bulb test (about three seconds after the igni-
tion switch is turned to the On position), replace the
malfunction indicator lamp bulb with a known good
unit. If the indicator lamp still fails to operate, diag-
nosis of the lamp, the instrument cluster circuitry, or
the CCD data bus should be performed with a DRB
scan tool as described in the proper Body Diagnostic
Procedures manual. Diagnosis of the Powertrain Con-
trol Module (PCM) should be performed with a DRB
scan tool as described in the proper Powertrain Diag-
nostic Procedures manual.

MASTER LIGHTING INDICATOR LAMP

The master lighting indicator shares the same cir-
cuitry as the cluster illumination lamps, and will
brighten and dim when the panel lamp dimmer
OR
switch is adjusted.
addresses an inoperative master lighting indicator
lamp condition. If the problem being diagnosed is
related to the dimming level of the master lighting
indicator lamp, diagnosis should be performed with a
DRB scan tool as described in the proper Body Diag-
nostic Procedures manual. For circuit 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
RESTRAINT SYSTEMS
STEERING WHEEL,
INSTRUMENT PANEL COMPONENT DIAGNOSIS OR
SERVICE. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
If only the master lighting indicator lamp is inop-
erative, replace the faulty bulb. If all of the cluster
illumination lamps are inoperative, proceed as fol-
lows.
(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
OR 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
The diagnosis found
TO GROUP 8M -
BEFORE ATTEMPTING
STEERING COLUMN,
ZG
here
PASSIVE
OR