Symptom Related Diagnostic Procedures

DEFOG RELAY CONTROL CKT SHORTED TO BATT





For a complete wiring diagram Consult Diagrams/Electrical

- When Monitored:
With the ignition on and the EBL switch depressed.

- Set Condition:
This DTC will set when the A/C Heater Control Module senses excessive current draw on the Rear Window Defogger Relay Control Circuit.





Diagnostic Test

1. CHECK FOR HVAC DTC'S
Turn the ignition on.
With the scan tool, record and erase DTC's.
Depress the EBL switch on the A/C Heater Control Module.
With the scan tool, read the active DTC's.
Does the scan tool display DEFOG RELAY CONTROL CKT SHORTED TO BATT?

Yes

- Go To2

No

- Using the wiring diagram/schematic as a guide, inspect the wiring and connectors. Refer to any Hotline letters or Technical Service Bulletins that may apply.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

2. REAR WINDOW DEOFGGER RELAY SHORTED TO BATTERY
Turn the ignition on.
With the scan tool, erase DTC's.
Turn the ignition off.
Remove and install a known good relay in place of the Rear Window Defogger Relay.
Turn the ignition on.
Depress the EBL Switch on the A/C Heater Control Module.
With the scan tool, read the active DTC's.
Does the scan tool display DEFOG RELAY CONTROL CKT SHORTED TO BATT?

Yes

- Go To3

No

- Replace the Rear Window Defogger Relay.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

3. REAR WINDOW DEFOGGER RELAY CONTROL CIRCUIT SHORTED TO BATTERY




Turn the ignition off.
Remove the Rear Window Defogger Relay from the Power Distribution Center.
Disconnect the A/C Heater Control Module C2 harness connector.
Measure the voltage of the (C80) Rear Window Defogger Relay Control circuit at the A/C Heater Control Module connector with the Ignition off and on.
Is there any voltage present?

Yes

- Repair the (C80) Rear Window Defogger Relay Control circuit for a short to battery.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

No

- Replace the A/C Heater Control Module.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test