B0283

DTC B0283

DTC DESCRIPTOR
DTC B0283 02: Electric Rear Defrost Circuit Short To Ground
DTC B0283 05: Electric Rear Defrost Circuit Short To Battery Or Open

DIAGNOSTIC FAULT INFORMATION
Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

CIRCUIT/SYSTEM DESCRIPTION
The body control module (BCM) monitors the voltage level on the supply voltage circuit of the RR DEFOG relay. The voltage level should be low while the RR DEFOG relay is de-energized. The voltage will be near system voltage when the BCM energizes the RR DEFOG relay.

CONDITIONS FOR RUNNING THE DTC
Battery voltage must be between 9-16 volts.

CONDITIONS FOR SETTING THE DTC
DTC B0283 02: This DTC will set when the BCM detects a short to ground in the RR DEFOG relay control circuit voltage supply circuit for 1 second or greater.
DTC B0283 05: This DTC will set when the BCM detects a short to voltage or an open/high resistance in the RR DEFOG relay control circuit voltage supply circuit for 1 second or greater.

ACTION TAKEN WHEN THE DTC SETS
- The BCM stores the DTC to memory.
- The rear window defogger will not operate.

CONDITIONS FOR CLEARING THE DTC
- This DTC will change from current to history when the fault is no longer present.
- A history DTC will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present.
- The technician issues a scan tool CLEAR DTCs command.

CIRCUIT/SYSTEM VERIFICATION
Ignition ON, command the rear window defogger ON and OFF with a scan tool. Observe the rear window defogger operation as the rear window defogger turns ON & OFF.
- If the rear window defogger indicator light does not illuminate, replace the HVAC control module.

CIRCUIT/SYSTEM TESTING

REAR DEFOGGER MALFUNCTION
1. Ignition OFF, disconnect the RR DEFOG relay.
2. Ignition OFF, test for less than 1.0 ohm of resistance between the coil side ground circuit terminal and ground.
- If greater than the specified range, test for an open/high resistance.

3. Ignition ON, verify that a test lamp does not illuminate between the switch side control circuit terminal and ground.
- If the test lamp illuminates, test the control circuit for a short to voltage.

4. Verify that a test lamp illuminates between the switch side B+ circuit terminal and ground.
- If the test lamp does not illuminate, test the switch side B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the switch side circuit fuse is open, test the switch side control circuit terminal for a short to ground.

5. Connect a test lamp between the coil side control circuit terminal and the coil side ground circuit terminal.
6. Command the RR DEFOG relay ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
- If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.
- If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.

7. If all circuits test normal, test or replace the RR DEFOG relay.

REPAIR INSTRUCTIONS
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
- Relay Replacement (Within an Electrical Center) Relay Replacement (Attached to Wire Harness)
- Control Module References for HVAC Control Module and BCM replacement, setup and programming.