
Symptom:
FRONT FOG LAMP RELAY OPEN
When Monitored and Set Condition:
FRONT FOG LAMP RELAY OPEN
When Monitored: Ignition On.
Set Condition: The IPM detects high current from the fog lamp relay control circuit.
POSSIBLE CAUSES
MISSING RELAY
OPEN FUSE
FOG LAMP RELAY
INTERMITTENT CONDITION
FOG LAMP RELAY CONTROL CIRCUIT OPEN
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 Relay Open?All
Ye s®Go To 2
No®Go To 5
2 Turn the ignition off.
Check the IPM to make certain the Fog Lamp Relay is present.
Is the Fog Lamp Relay present?All
Ye s®Go To 3
No®Replace the missing Fog Lamp Relay.
Perform BODY VERIFICATION TEST - VER 1.
3 Turn the ignition off.
Install a known good relay in place of the fog lamp relay.
Turn the Fog Lamps On.
Do the Fog Lamps operate normally?All
Ye s®Replace the Fog Lamp Relay.
Perform BODY VERIFICATION TEST - VER 1.
No®Go To 4
446
EXTERIOR LIGHTING

TEST ACTION APPLICABILITY
4 Turn the ignition off
Remove the Fog Lamp Relay.
Measure the voltage of the Fused B+ circuit of the fog lamp relay.
Is the voltage above 10 volts?All
Ye s®Replace the Front Control Module.
Perform BODY VERIFICATION TEST - VER 1.
No®Replace the Intelligent Power Module.
Perform BODY VERIFICATION TEST - VER 1.
5 Turn the ignition off.
Check the IPM Fog Lamp fuse #1.
Is the fuse open?All
Ye s®Replace the open fuse.
Perform BODY VERIFICATION TEST - VER 1.
No®Go To 6
6 Turn the ignition off.
Disconnect the Front Control Module from the IPM.
Remove the Fog Lamp Relay.
Measure the resistance of the Fog Lamp Relay Control Circuit.
Is the resistance below 5.0 ohms?All
Ye s®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.
No®Repair the Fog Lamp Relay Control Circuit.
Perform BODY VERIFICATION TEST - VER 1.
447
EXTERIOR LIGHTING
FRONT FOG LAMP RELAY OPEN ÐContinued

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

Symptom List:
A/C FAULT (STORED) - MANUAL A/C
BACKLIGHT DIMMING RX FAILURE (STORED) - MANUAL A/C
BLEND OVERCURRENT (STORED) - MANUAL A/C
CHECKSUM FAILURE (STORED) - MANUAL A/C
EVAPORATOR TEMPERATURE SENSOR CIRCUIT OPEN
(STORED) - MANUAL A/C
EVAPORATOR TEMPERATURE SENSOR CIRCUIT SHORT
(STORED) - MANUAL A/C
LOOPBACK FAILURE (STORED) - MANUAL A/C
LOOPBACK TEST FAILURE (STORED) - MANUAL A/C
MODE OVERCURRENT (STORED) - MANUAL A/C
NO BCM MESSAGE RECEIVED (STORED) - MANUAL A/C
NO PCM MESSAGE RECEIVED (STORED) - MANUAL A/C
PCM COMMUNICATION FAILURE (STORED) - MANUAL A/C
POWER FAULT (STORED) - MANUAL A/C
REAR BLEND OVERCURRENT (STORED) - MANUAL A/C
REAR BLEND POT CIRCUIT OPEN (STORED) - MANUAL A/C
REAR BLEND POT CIRCUIT SHORT (STORED) - MANUAL A/C
REAR DEFOG FAILURE (STORED) - MANUAL A/C
REAR MODE OVERCURRENT (STORED) - MANUAL A/C
RECIRC OVERCURRENT (STORED) - MANUAL A/C
RECIRCULATION FAULT (STORED) - MANUAL A/C
TX FAILURE (STORED) - MANUAL A/C
UNKNOWN FAULT DETECTED (STORED) - MANUAL A/C
VEHICLE ODOMETER FAILURE (STORED) - MANUAL A/C
ZONE OVERCURRENT (STORED) - MANUAL A/C
Test Note: All symptoms listed above are diagnosed using the same tests.
The title for the tests will be A/C FAULT (STORED) - MANUAL
A/C.
When Monitored and Set Condition:
A/C FAULT (STORED) - MANUAL A/C
When Monitored: With the ignition on.
Set Condition: This DTC will set if the A/C switch stays closed for 10 minutes.
BACKLIGHT DIMMING RX FAILURE (STORED) - MANUAL A/C
When Monitored: With the ignition on.
Set Condition: If the A/C - Heater Control Module does not receive the dimming function
message from the BCM for more than 5 seconds, then the A/C - Heater Control Module
LEDs will default to full brightness and the DTC will set.
514
HEATING & A/C

Symptom:
FRONT FOG LAMP INDICATOR OPEN
POSSIBLE CAUSES
INTERMITTENT WIRING AND CONNECTORS
FRONT FOG LAMP INDICATOR CIRCUIT OPEN
FRONT FOG LAMP INDICATOR GROUND CIRCUIT OPEN
FRONT FOG LAMP INDICATOR CIRCUIT SHORT TO VOLTAGE
HEADLAMP SWITCH
BODY CONTROL MODULE
TEST ACTION APPLICABILITY
1 Turn the ignition on.
With the DRBIIIt, record and erase Body Control Module DTC's.
Turn the ignition off, wait 15 seconds, then turn the ignition on.
Turn on the Front Fog Lamps.
With the DRBIIIt, read DTCs.
Does the DRBIIItdisplay FRONT FOG LAMP INDICATOR OPEN?All
Ye s®Go To 2
No®Go To 8
2 Turn the ignition off to the lock position.
Note: Check connectors - Clean/repair as necessary.
Ignition on, engine not running.
Turn ON the Front Fog Lamps.
Using a 12-volt test light connected to ground, back probe the Front Fog Lamp
Indicator circuit in the Headlamp Switch harness connector.
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®Go To 6
3 Turn the ignition off to the lock position.
Disconnect the Body Control Module harness connector.
Disconnect the Headlamp Switch harness connector.
Note: Check connectors - Clean/repair as necessary.
Measure the resistance of the Front Fog Lamp Indicator Ground circuit from the
Body Control Module harness connector to the Headlamp Switch harness connector.
Is the resistance above 5.0 ohms?All
Ye s®Repair the Front Fog Lamp Indicator Ground circuit for an open.
Perform BODY VERIFICATION TEST - VER 1.
No®Go To 4
567
INSTRUMENT CLUSTER

Symptom:
FRONT FOG LAMP INDICATOR SHORT TO GROUND
POSSIBLE CAUSES
INTERMITTENT WIRING AND CONNECTORS
FRONT FOG LAMP INDICATOR CIRCUIT SHORT TO GROUND
HEADLAMP SWITCH
BODY CONTROL MODULE
TEST ACTION APPLICABILITY
1 Turn the ignition on.
With the DRBIIIt, record and erase Body Control Module DTC's.
Turn the ignition off, wait 15 seconds, then turn the ignition on.
With the DRBIIIt, read DTCs.
Does the DRBIIItdisplay FRONT FOG LAMP INDICATOR SHORT TO GROUND?All
Ye s®Go To 2
No®Go To 6
2 Turn the ignition off to the lock position.
Note: Check connectors - Clean/repair as necessary.
Ignition on, engine not running.
Turn ON the Front Fog Lamps.
Using a 12-volt test light connected to ground, back probe the Rear Fog Lamp
Indicator circuit in the Headlamp Switch harness connector.
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®Go To 4
3 If there are no possible causes remaining, view repair. All
Repair
Replace the Headlamp Switch.
Perform BODY VERIFICATION TEST - VER 1.
4 Turn the ignition off to the lock position.
Disconnect the Body Control Module harness connector.
Disconnect the Headlamp Switch harness connector.
Note: Check connectors - Clean/repair as necessary.
Measure the resistance between ground and the Front Fog Lamp Indicator circuit.
Is the resistance below 5.0 ohms?All
Ye s®Repair the Front Fog Lamp Indicator circuit for a short to ground.
Perform BODY VERIFICATION TEST - VER 1.
No®Go To 5
5 If there are no possible causes remaining, view repair. All
Repair
Replace the Body Control Module.
Perform BODY VERIFICATION TEST - VER 1.
569
INSTRUMENT CLUSTER

Symptom:
REAR FOG INDICATOR OUTPUT OPEN
POSSIBLE CAUSES
INTERMITTENT WIRING AND CONNECTORS
REAR FOG LAMP INDICATOR CIRCUIT OPEN
REAR FOG LAMP INDICATOR GROUND CIRCUIT OPEN
REAR FOG LAMP INDICATOR CIRCUIT SHORT TO VOLTAGE
HEADLAMP SWITCH
BODY CONTROL MODULE
TEST ACTION APPLICABILITY
1 Turn the ignition on.
With the DRBIIIt, record and erase Body Control Module DTC's.
Turn the ignition off, wait 15 seconds, then turn the ignition on.
Turn on the Rear Fog Lamps.
With the DRBIIIt, read DTCs.
Does the DRBIIItdisplay REAR FOG LAMP INDICATOR OPEN?All
Ye s®Go To 2
No®Go To 8
2 Turn the ignition off to the lock position.
Note: Check connectors - Clean/repair as necessary.
Ignition on, engine not running.
Turn ON the Rear Fog Lamps.
Using a 12-volt test light connected to ground, back probe the Rear Fog Lamp
Indicator circuit in the Headlamp Switch harness connector.
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®Go To 6
3 Turn the ignition off to the lock position.
Disconnect the Body Control Module harness connector.
Disconnect the Headlamp Switch harness connector.
Note: Check connectors - Clean/repair as necessary.
Measure the resistance of the Rear Fog Lamp Indicator Ground circuit from the Body
Control Module harness connector to the Headlamp Switch harness connector.
Is the resistance above 5.0 ohms?All
Ye s®Repair the Rear Fog Lamp Indicator Ground circuit for an open.
Perform BODY VERIFICATION TEST - VER 1.
No®Go To 4
600
INSTRUMENT CLUSTER

Symptom:
REAR FOG INDICATOR OUTPUT SHORT
POSSIBLE CAUSES
INTERMITTENT WIRING AND CONNECTORS
REAR FOG LAMP INDICATOR CIRCUIT SHORT TO GROUND
HEADLAMP SWITCH
BODY CONTROL MODULE
TEST ACTION APPLICABILITY
1 Turn the ignition on.
With the DRBIIIt, record and erase Body Control Module DTC's.
Turn the ignition off, wait 15 seconds, then turn the ignition on.
With the DRBIIIt, read DTCs.
Does the DRBIIItdisplay REAR FOG LAMP INDICATOR SHORT TO GROUND?All
Ye s®Go To 2
No®Go To 6
2 Turn the ignition off to the lock position.
Note: Check connectors - Clean/repair as necessary.
Ignition on, engine not running.
Turn ON the Rear Fog Lamps.
Using a 12-volt test light connected to ground, back probe the Rear Fog Lamp
Indicator circuit in the Headlamp Switch harness connector.
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®Go To 4
3 If there are no possible causes remaining, view repair. All
Repair
Replace the Headlamp Switch.
Perform BODY VERIFICATION TEST - VER 1.
4 Turn the ignition off to the lock position.
Disconnect the Body Control Module harness connector.
Disconnect the Headlamp Switch harness connector.
Note: Check connectors - Clean/repair as necessary.
Measure the resistance between ground and the Rear Fog Lamp Indicator circuit.
Is the resistance below 5.0 ohms?All
Ye s®Repair the Rear Fog Lamp Indicator circuit for a short to ground.
Perform BODY VERIFICATION TEST - VER 1.
No®Go To 5
5 If there are no possible causes remaining, view repair. All
Repair
Replace the Body Control Module.
Perform BODY VERIFICATION TEST - VER 1.
602
INSTRUMENT CLUSTER