Electrically Heated Systems

DEFOG RELAY CONTROL CKT SHORTED TO BATT

Defog Relay Control Ckt Shorted To Batt:

WHEN MONITORED
With the Ignition on and the EBL (Rear Defogger) switch depressed.

SET CONDITION
This DTC will set if the A/C Heater Control senses excessive current on the (C110) Defogger Relay Control circuit.

POSSIBLE CAUSES
- HVAC DTCs
- Relay shorted
- (C110) Defogger relay control circuit shorted to battery
- A/C Heater control shorted to battery
- Integrated power module

Diagnostic Test

1. CHECK FOR HVAC DTC'S
Turn the ignition on.
With the DRBIII(R), record and erase DTCs.
Depress the EBL Switch on the A/C Heater Control.
With the DRBIII(R), read the active DTCs.

Q: Does the DRBIII(R) display DEFOG RELAY CONTROL CKT SHORTED TO BATT?

YES: Go To 2
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. CHECK THE RELAY FOR A SHORT TO BATTERY
Turn the ignition off.
One at a time remove and install a known good relay in place of the Heated Mirror Relay and then the EBL relay if equipped.

NOTE: Do the following steps for each relay.

Turn the ignition on.
With the DRBIII(R), record and erase DTCs.
Depress the EBL Switch on the A/C Heater Control.
With the DRBIII(R), read the active DTCs.

Q: Does the DRBIII(R) display DEFOG RELAY CONTROL CKT SHORTED TO BATT?

YES: Go To 3
NO: Replace the Relay that set the DTC. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

3. CHECK FOR A SHORTED A/C HEATER CONTROL




Turn the ignition off.
Remove the Heated Mirror Relay and the EBL relay if equipped from the Integrated Power Module.
Disconnect the A/C Heater Control C1 harness connector.
Turn the ignition on.
Measure the voltage of the (C110) Defogger Relay Control circuit at the A/C Heater Control C1 harness connector.

Q: Is there any voltage present?

YES: Go To 4
NO: Replace the A/C Heater Control. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

4. CHECK THE (C110) DEFOGGER RELAY CONTROL CIRCUIT FOR A SHORT TO BATTERY




Turn the ignition off.
Disconnect the Integrated Power Module C5 harness connector.
Turn the ignition on.
Measure the voltage of the (C110) Defogger Relay Control circuit at the A/C Heater Control C1 harness connector.

Q: Is there any voltage present?

YES: Repair the (C110) Defogger Relay Control circuit for a short to battery. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Replace the Integrated Power Module. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test