Rear Defogger Switch Sense Circuit

WHEN MONITORED
With the ignition on.

SET CONDITION
The Body Control Module (BCM) detects a short to power, ground, or an open on the Rear Defogger Switch Sense circuit.

POSSIBLE CAUSES
- Rear defogger switch sense circuit short to voltage
- Rear defogger switch sense circuit short to ground
- Rear defogger switch sense circuit open
- Body control module

Diagnostic Test




1. MEASURE THE RESISTANCE OF THE REAR DEFOGGER SWITCH SENSE CIRCUIT

Turn the ignition off.
Disconnect the BCM harness connector.
Disconnect the A/C Heater Control Module harness connector.

NOTE: Check connector - Clean/repair as necessary.

Measure the resistance of the Rear Defogger Switch Sense circuit from the BCM harness connector to the A/C Heater Control Module harness connector.

Q: Is the resistance below 5.0 ohms?

YES: Go to 2
NO: Repair the Rear Defogger Switch Sense circuit for an open. Perform BODY VERIFICATION TEST. Body Verification Test




2. MEASURE THE VOLTAGE OF THE REAR DEFOGGER SWITCH SENSE CIRCUIT

Turn the ignition on.

Measure the voltage of the Rear Defogger Switch Sense circuit at the A/C Heater Control Module harness connector.

Q: Is voltage present?

YES: Repair the Rear Defogger Switch Sense circuit for a short to voltage. Perform BODY VERIFICATION TEST. Body Verification Test
NO: Go to 3




3. MEASURE THE RESISTANCE OF THE REAR DEFOGGER SWITCH SENSE CIRCUIT

Turn the ignition on.
Measure the resistance between ground and the Rear Defogger Switch Sense circuit.

Q: Is the resistance below 10 kohms?

YES: Repair the Rear Defogger Switch Sense circuit for a short to ground. Perform BODY VERIFICATION TEST. Body Verification Test
NO: Replace the Body Control Module. Perform BODY VERIFICATION TEST. Body Verification Test