B106C
B106C REAR DEFROST CONTROL CIRCUIT HIGH - FCMB106C - Rear Defrost Control Circuit High - FCM:
WHEN MONITORED
Continuously
SET CONDITION
When the Front Control Module detects a short to battery on the Defogger Relay Control circuit.
POSSIBLE CAUSES
- Rear window defogger relay
- (C115) Defogger relay control
- Front control module
Diagnostic Test
1. TEST FOR INTERMITTENT CONDITION
With the scan tool, record and erase DTC's
Operate the Rear Window Defogger switch several times.
Cycle the ignition from on to off 3 times and leave on.
With the scan tool, read DTC's.
Q: Does the scan tool display B106C - REAR DEFROST CONTROL CIRCUIT HIGH?
YES: Go To 2
NO: The conditions that caused this code to set are not present at this time. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
2. REAR DEFOGGER RELAY
Turn the ignition off.
Install a known good relay in place of the Rear Window Defogger Relay.
With the scan tool erase DTC's
Operate the Rear Window Defogger Switch several times.
Cycle the ignition from on to off 3 times and leave on.
With the scan tool, read DTC's.
Q: Does the scan tool display B106C - REAR DEFROST CONTROL CIRCUIT HIGH?
NO: Replace the original Rear Window Defogger Relay. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
YES: Go To 3
3. (C115)-DEFOGGER RELAY CONTROL CIRCUIT
Remove the Rear Window Defogger Relay.
Disconnect the Front Control Module from the PDC 49 - way connector.
Turn the ignition on.
Measure the voltage between (C115) Defogger Relay Control circuit and ground.
Q: Is there any voltage present?
YES: Repair the (C115) Defogger Relay Control circuit for a short to voltage. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Replace the Front Control Module. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test