B0283

DTC B0283

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.



DTC Descriptors
DTC B0283 02
- Electric Rear Defrost Circuit Short to Ground or Open

DTC B0283 05
- Electric Rear Defrost Circuit Short to Battery or Open




Diagnostic Fault Information






Circuit/System Description

The HVAC control module 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 HVAC control module energizes the RR-Defog relay.


Conditions for Running the DTC

Battery voltage must be between 9-16 volts.


Conditions for Setting the DTC

B0283 02

When the HVAC control module detects a short to ground or an open/high resistance in the RR-Defog relay coil control circuit for 1 second or greater

B0283 05

When the HVAC control module detects a short to battery or an open/high resistance in the RR-Defog relay coil control circuit for 1 second or greater.


Action Taken When the DTC Sets

The rear window defogger will malfunction.


Conditions for Clearing the DTC

* The DTC will be current for as long as the fault is present.
* When the fault is no longer present, the DTC will be a history DTC.
* A history DTC will clear after 50 ignition cycles.



Reference Information
Schematic Reference

Defogger Schematics ([1][2]Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Rear Window Defogger Description and Operation (Rear Window Defogger Description and Operation)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information


Circuit/System Verification

Command the Rear Defog Request ON and OFF with the scan tool. The rear window defogger should turn ON and OFF when changing between the commanded states.


Circuit/System Testing

1. Ignition OFF, disconnect the RR-Defog relay.
2. Test for less than 1 ohm between the ground circuit terminal 85 and ground.

• If greater than the specified range, test the ground circuit for an open/high resistance

3. Connect a test lamp between the control circuit terminal 86 and the ground circuit terminal 85.
4. Ignition ON, command the Rear Defog Request 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 HVAC control module.
• 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 HVAC control module.

5. If all circuits test normal, test or replace the RR-Defog relay.



Component Testing

1. Ignition OFF, disconnect the RR-Defog relay.
2. Test for 60-180 ohms between terminals 85 and 86.

• If the not within the specified range, replace the relay.

3. Test for infinite resistance between the following terminals:

* 30 and 86
* 30 and 87
* 30 and 85
* 85 and 87


• If not the specified value, replace the relay.

4. Install a 25A fused jumper wire between relay terminal 85 and 12 volts. Install a jumper wire between relay terminal 86 and ground. Test for less than 2 ohms between terminals 30 and 87.

• If greater than the specified range, replace the relay.




Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Relay Replacement (Attached to Wire Harness) (Relay Replacement (Attached to Wire Harness))Relay Replacement (Within an Electrical Center) (Relay Replacement (Within an Electrical Center))
* Control Module References (Programming and Relearning) for HVAC control module replacement, setup and programming