B0283

DTC B0283

Circuit Description

The HVAC Control Module controls the REAR WINDOW DEFOGGER relay circuit. When the ignition switch is in Run position and the operator has depressed the defogger switch, the HVAC Control Module provides ground to the REAR WINDOW DEFOGGER relay control circuit.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B0283 Electric Rear Defrost

Conditions for Running the DTC

The system voltage must be between 9-16 volts.

Conditions for Setting the DTC

* The HVAC Control Module detects a short to battery positive voltage in the REAR WINDOW DEFOGGER relay control circuit when the HVAC Control Module is trying to energize the relay.
* The HVAC Control Module detects that the REAR WINDOW DEFOGGER relay control circuit is open.
* The condition above must be present for more than 1 second.

Action Taken When the DTC Sets

* The HVAC Control Module stores DTC B0283 in memory.
* The rear window defogger will not operate.

Conditions for Clearing the DTC

* A current DTC clears when the malfunction is no longer present.
* A history DTC clears when the module ignition cycle counter reaches the reset threshold, without a repeat of the malfunction.

Test Description

Step 1 - Step 11:

The numbers below refer to the step numbers on the diagnostic table.
2. Tests for battery positive voltage at the coil side of the dear window defogger relay. The BATT MAIN 3 fuse supplies power to the coil side of the REAR WINDOW DEFOGGER relay.
3. Tests the control circuit side of the REAR WINDOW DEFOGGER relay for faults that cause DTC B0283.
4. Listen for an audible click when the REAR WINDOW DEFOGGER relay operates. Command both the ON and OFF states. Repeat the commands as necessary.
5. Verifies that the HVAC Control Module is providing ground to the REAR WINDOW DEFOGGER relay.