Circuit Description
The body control module (BCM) controls the Rear Window Defogger relay circuit. When the ignition switch is in Run position and the operator has depressed the defogger switch, the BCM provides battery negative voltage to the Rear Window Defogger relay control circuit and the Electronic Compass module. The Electronic Compass module translates the signal to Compass Data which is then transmitted to the driver information center (DIC) for display of the Rear Defogger mode.
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 in the Rear Window Defogger relay control circuit when the BCM is trying to energize the relay. |
| • | The BCM 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 BCM 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
The numbers below refer to the step numbers on the diagnostic table.
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Tests for battery positive voltage at the coil side of the Rear Window Defogger relay. The BATT MAIN 3 fuse supplies power to the coil side of the Rear Window Defogger relay.
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Tests the control circuit side of the Rear Window Defogger relay for faults that cause both B0283 DTC.
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Listen for an audible click when the Rear Window Defogger relay operates. Command both the ON and OFF states. Repeat the commands as necessary.
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Verifies that the BCM is providing ground to the Rear Window Defogger relay.
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 8 | |
Did you find and correct the condition? | Go to Step 11 | Go to Step 4 | |
Does the test lamp turn ON and OFF? | Go to Step 6 | Go to Step 5 | |
Test the control circuit of the Rear Window Defogger relay for an open. Refer to Circuit Testing in Wiring Systems. Did you find and correct the condition? | Go to Step 11 | Go to Step 7 | |
6 | Inspect for poor connections and terminal damage at the relay socket. 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 11 | Go to Step 9 |
7 | 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 11 | Go to Step 10 |
8 | Repair the short to ground, poor connection or an open in the BATT 3 fused voltage supply circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 11 | -- |
9 | Replace the Rear Window Defogger relay. Refer to Relay Replacement in Wiring Systems. Did you complete the replacement? | Go to Step 11 | -- |
10 | 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 11 | -- |
11 |
Does the DTC reset? | Go to Step 2 | System OK |
