Jeep 1997 Grand Cherokee Service Manual page 1394

8W - 51 - 8
DESCRIPTION AND OPERATION
TAIL LAMPS, REAR LICENSE PLATE LAMPS AND
SIDE MARKER LAMPS
Circuit A6 from fuse 13 in the Power Distribution
Center (PDC) feeds circuit 366 through fuse 17 in the
junction block. Circuit 366 connects to the headlamp
switch.
When the headlamp switch is in the PARK or LOW
position, the switch connects circuit 366 to circuit
L90. From the headlamp switch, circuit L90 branches
to power the front parking lamps and rear license
plate lamps. Circuit L90 connects to circuits L21 and
L22. Circuits L21 and L22 feed the tail lamps and
side marker lamps. If the vehicle is equipped with a
lamp outage module, circuit L90 feeds the module
and the module powers the rear tail, license plate
and side marker lamps.
The Body Control Module (BCM) operates the park
lamps when it senses unauthorized entry to the vehi-
cle while the Vehicle Theft Security System is armed.
When it sense unauthorized entry, the BCM ener-
gizes the park lamp relay by providing ground for the
relay coil on circuit L79. Circuit 366 powers the relay
coil and contacts. When the relay energizes, it con-
nects circuit 366 to circuit L90.
Circuit Z1 provides a ground for the parking
lamps, tail lamps, and rear license plate lamps.
HELPFUL INFORMATION
• If the vehicle is equipped with factory installed
trailer tow, circuit L90 connects to the trailer tow
harness.
• Check fuse 13 in PDC.
• Check fuse 17 in the junction block.
STOP LAMPS AND CHMSL LAMPS
Circuit A250 from fuse 11 in the Power Distribu-
tion Center (PDC) supplies voltage to circuit L16
through fuse 9 in the junction block. Circuit L16 con-
nects to the stop lamp switch.
When the operator presses the brake pedal, the
stop lamp switch closes and connects circuit L16 to
circuit L50. Circuit L50 connects to circuits L73, L74
and L87. Circuit L73 and L74 feed the stop lamps.
Circuit L87 powers the Center High Mounted Stop
Lamps (CHMSL). Circuit Z1 provides a ground for
the stop lamps and CHMSL lamps.
If the vehicle is equipped with a lamp outage mod-
ule, circuit L50 connects to the module. The lamp
outage module powers circuit L73, L74 and L87.
8W - 51 REAR LIGHTING
8W-51 REAR LIGHTING
REAR FOG LAMPS
lamp relay on circuit L36. The relay coil and contacts
are powered by circuit L95 from fuse 15 in the fuse
block. The relay coil ground is controlled by the head-
lamp and rear fog lamp switches on circuit L96.
BACK-UP LAMPS
circuit A1 from fuse 8 in the Power Distribution Cen-
ter (PDC) to circuit A22. Circuit A22 powers circuit
F83 through fuse 6 in the junction block
TRAL position switch. When the operator puts the
transmission in REVERSE, the switch connects cir-
cuit F83 to circuit L10. Circuit L10 feeds the back-up
lamps. Circuit Z1 provides ground for the back-up
lamps.
HELPFUL INFORMATION
tion block.
switch when it is closed.
LAMP OUTAGE MODULE (LOM)
rear lighting lamp is not operating. When the igni-
tion switch is in the START or RUN position, circuit
A1 from fuse 8 in the Power Distribution Center
(PDC) connects to circuit A21. Circuit A21 feeds cir-
cuit F87 through fuse 5 in the junction block. Cir-
cuits F87 feeds the LOM.
Information Center (VIC). When the LOM senses a
inoperative lamp, the VIC displays the data to the
vehicle operator.
marker lamps, connects to the LOM. From the LOM,
circuit L90 continues to the license plate lamps. Cir-
cuits L21 and L22 from the LOM power the tail
lamps and side marker lamps.
the LOM. From the LOM, circuits L73 and L74
power the stop lamps and circuit L87 powers the
Center High Mounted Stop Lamps (CHMSL).
The rear fog lamps are powered by the rear fog
In the RUN position, the ignition switch connects
Circuit F83 supplies power to the PARK/NEU-
• Check fuse 8 in the PDC and fuse 6 in the junc-
• Check for continuity across the back-up lamp
The Lamp Outage Module (LOM) determines if a
Circuit G46 from the LOM connects to the Vehicle
Circuit L90 which feeds the tail lamps and side
Circuit L50 from the stop lamp switch connects to
Circuit Z1 grounds the LOM.
ZG