Circuit Description
The body control module (BCM) controls the RR defog relay. When the ignition switch is in RUN position and the operator has depressed the defogger switch, the BCM provides a ground signal on the rear defog relay control circuit energizing the relay.
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 BCM detects a short to voltage or short to ground in the rear defog relay control circuit. |
| • | The BCM detects that the rear defog relay control circuit is open. |
| • | Battery positive voltage to the RR defog relay is open or shorted to ground. |
| • | The RR defog relay coil is open. |
| • | The condition above must be present for more than 1 second. |
Action Taken When the DTC Sets
| • | The BCM stores DTC B0283 in memory. |
| • | The rear window defogger will not operate or, if shorted to ground will always be ON. |
Conditions for Clearing the DTC
| • | A current DTC clears when the malfunction is no longer present. |
| • | A history DTC will clear after 100 consecutive ignition cycles without a fault present. |
| • | History and current DTC can be cleared using a scan tool. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step tests for battery positive voltage at the coil side of the RR defog relay. The RR DEFOG fuse supplies power to the coil side of the RR defog relay.
-
Command both the ON and OFF states. Repeat the commands as necessary.
Step | Action | Yes | No | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Defogger Schematics Connector End View Reference: Stationary Windows Connector End Views | |||||||||||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information | ||||||||
Does the test lamp illuminate? | Go to Step 3 | Go to Step 7 | |||||||||
Does the test lamp turn ON and OFF as expected? | Go to Step 5 | Go to Step 4 | |||||||||
4 | Test the rear defog relay control circuit of the RR defog relay for the following:
Refer to Circuit Testing in Wiring Systems. Did you find and correct the condition? | Go to Step 10 | Go to Step 6 | ||||||||
5 | Inspect for poor connections at the harness connector of the RR defog relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 10 | Go to Step 8 | ||||||||
6 | Inspect for poor connections at the harness connector of the body control module (BCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 10 | Go to Step 9 | ||||||||
7 | Repair the following in the battery positive voltage circuit of the RR defog relay or a short to ground in the rear defog element supply voltage circuit:
Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 10 | -- | ||||||||
8 | Replace the RR defog relay. Refer to Relay Replacement in Wiring Systems. Did you complete the replacement? | Go to Step 10 | -- | ||||||||
9 | Replace the BCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | Go to Step 10 | -- | ||||||||
10 |
Does the DTC reset? | Go to Step 2 | System OK | ||||||||
