Page 454 of 4284

TEST ACTION APPLICABILITY
7 Disconnect the negative battery cable.
Measure the resistance between ground and the PCI Bus circuit at the Diagnostic
Junction Port tester that previously measured below 100.0 ohms.
Disconnect the module harness connector(s). Note: If the problem occurred on pins 1,
3, 9 or 12 of the Diagnostic Junction Port tester, observe the ohmmeter while
disconnecting each module connector one at a time.
Is the resistance below 100.0 ohms with the module(s) disconnected?All
Ye s®Repair the PCI Bus circuit that measured below 100.0 ohms for a
short to ground.
Perform BODY VERIFICATION TEST - VER 1.
No®Replace the module that when disconnected the short to ground
was eliminated.
Perform BODY VERIFICATION TEST - VER 1.
8 Turn the ignition off.
Note: Visually inspect the related wiring harness. Look for any chafed,
pierced, pinched, or partially broken wires.
Note: Visually inspect the related wire harness connectors. Look for broken,
bent, pushed out, or corroded terminals.
Were any problems found?All
Ye s®Repair wiring harness/connectors as necessary.
Perform BODY VERIFICATION TEST - VER 1.
No®Test Complete.
425
COMMUNICATION
*PCI BUS COMMUNICATION FAILURE ÐContinued
Page 471 of 4284

Symptom:
EBL RUN ONLY RELAY SHORTED TO BATTERY
When Monitored and Set Condition:
EBL RUN ONLY RELAY SHORTED TO BATTERY
When Monitored: Continuously with the ignition on.
Set Condition: The FCM has detected a short to battery voltage in the Rear Defogger
Relay control circuit.
POSSIBLE CAUSES
VERIFY ACTIVE DTC
FRONT CONTROL MODULE
INTELLIGENT POWER MODULE
REAR WINDOW DEFOGGER RELAY
TEST ACTION APPLICABILITY
1 Turn the ignition on.
With the DRBIIIt, erase the current Front Control Module DTC's.
Turn the ignition off, wait 10 seconds then turn the ignition on.
With the DRBIIIt, read the current Front Control Module DTC's.
Does the DRBIIItdisplay EBL RUN ONLY RELAY SHORTED TO BATTERY
trouble code?All
Ye s®Go To 2
No®The condition that caused this symptom is currently not present
at this time.
Perform BODY VERIFICATION TEST - VER 1.
2 Turn the ignition off.
Install a known good relay in place of the Rear Window Defogger relay.
Turn the ignition on.
Attempt to operate the Rear Window Defogger.
With the DRBIIIt, read the current Front Control Module DTCs.
Did the DTC reset?All
Ye s®Go To 3
No®Replace the Rear Defogger Relay.
Perform BODY VERIFICATION TEST - VER 1.
3 Turn the ignition off.
Remove the Rear Window Defogger Relay from the IPM.
Remove the Front Control Module from the IPM.
Measure the voltage of the Rear Window Relay Control circuit.
Is the voltage above 1.0 volts?All
Ye s®Replace the Fuse and Relay Center.
Perform BODY VERIFICATION TEST - VER 1.
No®Replace the Front Control Module.
Perform BODY VERIFICATION TEST - VER 1.
442
ELECTRICALLY HEATED SYSTEMS
Page 477 of 4284

Symptom:
FRONT FOG LAMP SHORTED TO BATTERY
When Monitored and Set Condition:
FRONT FOG LAMP SHORTED TO BATTERY
When Monitored: Ignition On.
Set Condition: When a battery fault condition is present.
POSSIBLE CAUSES
INTERMITTENT CONDITION
FOG LAMP RELAY
FRONT CONTROL MODULE
INTELLIGENT POWER MODULE
TEST ACTION APPLICABILITY
1 Turn the ignition on.
With the DRBIIIt, clear all IPM DTC's.
Turn the Fog Lamps on.
With the DRBIIIt, read the DTC information.
Does the DRBIIItread: Front Fog Lamp Shorted To Battery?All
Ye s®Go To 2
No®The condition that caused the symptom is currently not present.
Inspect the related wiring for a possible intermittent condition.
Look for any chafed, pierced,pinched, or partially broken wires.
Perform BODY VERIFICATION TEST - VER 1.
2 Turn the ignition off.
Remove and install a known good relay in place of the Fog Lamp Relay.
Do the Fog Lamps operate normally?All
Ye s®Replace the Fog Lamp Relay.
Perform BODY VERIFICATION TEST - VER 1.
No®Go To 3
3 Turn the ignition off.
Remove the Fog Lamp Relay from the IPM.
Remove the Front Control Module from the IPM.
Measure the voltage of the Fog Lamp Relay Control circuit and ground.
Is the voltage above 1.0 volts?All
Ye s®Replace the Intelligent Power Module.
Perform BODY VERIFICATION TEST - VER 1.
No®Replace the Front Control Module.
Perform BODY VERIFICATION TEST - VER 1.
448
EXTERIOR LIGHTING
Page 491 of 4284

Symptom:
LEFT HIGH BEAM HEADLAMP CIRCUIT OPEN
POSSIBLE CAUSES
FRONT CONTROL MODULE
GROUND CIRCUIT OPEN
LEFT HEADLAMP
LEFT HIGH BEAM DRIVER CIRCUIT OPEN
WIRING HARNESS INSPECTION
TEST ACTION APPLICABILITY
1 Turn the ignition on.
With the DRB, erase the Front Control Module DTC's.
Turn the headlamps on.
Switch the headlamps between high beam and low beam several times, pausing for
5 seconds in each position.
With the DRB, read Front Control Module DTC's.
Is this DTC present?All
Ye s®Go To 2
No®Go To 5
2 Turn the ignition off.
Disconnect the Left Headlamp harness connector.
Using a 12-volt test light connected to 12-volts, check the Ground circuit.
NOTE: The test light must illuminate brightly. Compare the brightness to
that of a direct connection to the battery.
Does the test light illuminate brightly?All
Ye s®Go To 3
No®Repair the Ground circuit for an open.
Perform BODY VERIFICATION TEST - VER 1.
3 Turn the ignition off.
Disconnect the Left Headlamp.
Disconnect the Front Control Module from the Intelligent Power Module.
Measure the resistance of the Left High Beam Driver circuit.
Is the resistance below 10.0 ohms?All
Ye s®Go To 4
No®Repair the Left High Beam Driver circuit for an open.
Perform BODY VERIFICATION TEST - VER 1.
462
EXTERIOR LIGHTING
Page 492 of 4284

TEST ACTION APPLICABILITY
4 Turn the ignition off.
Disconnect the Left Headlamp harness connector.
Using a 12-volt test light connected to ground, check the Left High Beam Driver
circuit in the Left Headlamp harness connector.
Turn the high beam headlamps on.
NOTE: The test light must illuminate brightly. Compare the brightness to
that of a direct connection to the battery.
Does the test light illuminate brightly?All
Ye s®Replace the Left Headlamp Bulb.
Perform BODY VERIFICATION TEST - VER 1.
No®Replace the Front Control Module.
Perform BODY VERIFICATION TEST - VER 1.
5 Turn the ignition off.
NOTE: Visually inspect the related wiring harness and circuits. Look for
any chafed, pierced, pinched, or partially broken wires.
NOTE: Visually inspect the related wiring harness connectors. Look for
broken, bent, pushed out, or corroded terminals.
Note: Refer to any Technical Service Bulletins (TSB) that may apply.
Were any problems found?All
Ye s®Repair as necessary.
Perform BODY VERIFICATION TEST - VER 1.
No®Test Complete.
463
EXTERIOR LIGHTING
LEFT HIGH BEAM HEADLAMP CIRCUIT OPEN ÐContinued
Page 495 of 4284

Symptom:
LEFT HIGH BEAM HEADLAMP CIRCUIT SHORTED TO VOLTAGE
POSSIBLE CAUSES
FRONT CONTROL MODULE
GROUND CIRCUIT OPEN
HIGH BEAM AND LOW BEAM DRIVERS CIRCUITS SHORTED TOGETHER
LEFT HEADLAMP
LEFT HIGH BEAM DRIVER CIRCUIT SHORTED TO VOLTAGE
WIRING PROBLEM
WIRING HARNESS INSPECTION
TEST ACTION APPLICABILITY
1 Turn the ignition on.
With the DRB, erase the Front Control Module DTC's.
Turn the headlamps on.
Switch the headlamps between high beam and low beam several times, pausing for
5 seconds in each position.
With the DRB, read Front Control Module DTC's.
Is this DTC present?All
Ye s®Go To 2
No®Go To 7
2 Turn the ignition off.
Disconnect the Left Headlamp harness connector.
Using a 12-volt test light connected to 12-volts, check the Ground circuit.
NOTE: The test light must illuminate brightly. Compare the brightness to
that of a direct connection to the battery.
Does the test light illuminate brightly?All
Ye s®Go To 3
No®Repair the Ground circuit for an open.
Perform BODY VERIFICATION TEST - VER 1.
3 Turn the ignition off.
Disconnect the Left Headlamp harness connector.
Disconnect the Front Control Module.
Measure the resistance between the Left High Beam Driver circuit and the Left Low
Beam Driver circuit at the Left Headlamp harness connector.
Is the resistance below 100.0 ohms?All
Ye s®Repair the Left High Beam Driver circuit for a short to the Left
Low Beam Driver circuit.
Perform BODY VERIFICATION TEST - VER 1.
No®Go To 4
466
EXTERIOR LIGHTING
Page 497 of 4284

Symptom:
LEFT LOW BEAM HEADLAMP CIRCUIT OPEN
POSSIBLE CAUSES
FRONT CONTROL MODULE
GROUND CIRCUIT OPEN
LEFT HEADLAMP
LEFT LOW BEAM DRIVER CIRCUIT OPEN
WIRING HARNESS INSPECTION
TEST ACTION APPLICABILITY
1 Turn the ignition on.
With the DRB, erase the Front Control Module DTC's.
Turn the headlamps on.
Switch the headlamps between high beam and low beam several times, pausing for
5 seconds in each position.
With the DRB, read Front Control Module DTC's.
Is this DTC present?All
Ye s®Go To 2
No®Go To 5
2 Turn the ignition off.
Disconnect the Left Headlamp harness connector.
Using a 12-volt test light connected to 12-volts, check the Ground circuit.
NOTE: The test light must illuminate brightly. Compare the brightness to
that of a direct connection to the battery.
Does the test light illuminate brightly?All
Ye s®Go To 3
No®Repair the Ground circuit for an open.
Perform BODY VERIFICATION TEST - VER 1.
3 Turn the ignition off.
Disconnect the Left Headlamp.
Disconnect the Front Control Module from the Intelligent Power Module.
Measure the resistance of the Left Low Beam Driver circuit.
Is the resistance below 10.0 ohms?All
Ye s®Go To 4
No®Repair the Left Low Beam Driver circuit for an open.
Perform BODY VERIFICATION TEST - VER 1.
468
EXTERIOR LIGHTING
Page 498 of 4284

TEST ACTION APPLICABILITY
4 Turn the ignition off.
Disconnect the Left Headlamp harness connector.
Using a 12-volt test light connected to ground, check the Left Low Beam Driver
circuit in the Left Headlamp harness connector.
NOTE: The test light must illuminate brightly. Compare the brightness to
that of a direct connection to the battery.
Turn the low beam headlamps on.
Does the test light illuminate brightly?All
Ye s®Replace the Left Headlamp Bulb.
Perform BODY VERIFICATION TEST - VER 1.
No®Replace the Front Control Module.
Perform BODY VERIFICATION TEST - VER 1.
5 Turn the ignition off.
NOTE: Visually inspect the related wiring harness and circuits. Look for
any chafed, pierced, pinched, or partially broken wires.
NOTE: Visually inspect the related wiring harness connectors. Look for
broken, bent, pushed out, or corroded terminals.
Note: Refer to any Technical Service Bulletins (TSB) that may apply.
Were any problems found?All
Ye s®Repair as necessary.
Perform BODY VERIFICATION TEST - VER 1.
No®Test Complete.
469
EXTERIOR LIGHTING
LEFT LOW BEAM HEADLAMP CIRCUIT OPEN ÐContinued