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 Descriptor
DTC B0283 00
- Rear Window Heating Circuit Malfunction




Diagnostic Fault Information






Circuit/System Description

The rear fuse block monitors the voltage level on the supply voltage circuit of the REAR DEFROST relay. The voltage level should be low while the REAR DEFROST relay is de-energized. The voltage will be near system voltage when the rear fuse block energizes the REAR DEFROST relay.


Conditions for Running the DTC

Battery voltage must be between 9-16 volts.


Conditions for Setting the DTC

When the rear fuse block detects a fault in the relay control circuit for 1 second or greater.


Action Taken When the DTC Sets

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.



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

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 and OFF.


Circuit/System Testing

1. Ignition OFF, disconnect the REAR DEFROST relay.
2. Connect a test lamp between the B+ circuit terminal 85 and the control circuit terminal 86.
3. Ignition ON, command the rear 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 rear fuse block.
• 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 rear fuse block.

4. If all circuits test normal, test or replace the REAR DEFROST relay.



Component Testing

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

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

4. Install a 40A 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 (Within an Electrical Center) (Relay Replacement (Within an Electrical Center))Relay Replacement (Attached to Wire Harness) (Relay Replacement (Attached to Wire Harness))
* Control Module References (Programming and Relearning)for rear fuse block replacement, setup, and programming