GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2007 🢒 Lucerne 🢒 DTC 🢒 DTC B0283

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 ground 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 instrument panel cluster (IPC) 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 battery positive 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.

  1. Tests for battery positive voltage at the coil side of the dear window defogger relay. The BATT MAIN 3 fuse supplies power to the coil side of the REAR WINDOW DEFOGGER relay.

    2.

  2. Tests the control circuit side of the REAR WINDOW DEFOGGER relay for faults that cause DTC B0283.

    3.

  3. Listen for an audible click when the REAR WINDOW DEFOGGER relay operates. Command both the ON and OFF states. Repeat the commands as necessary.

    4.

  4. Verifies that the BCM is providing ground to the REAR WINDOW DEFOGGER relay.

Step

Action

Yes

No

Schematic Reference: Moveable Window Schematics

Connector End View Reference: Window Systems Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Remove the REAR WINDOW DEFOGGER relay.
  2. Connect a test lamp between the REAR WINDOW DEFOGGER relay BATT main 3 fused voltage supply circuit and ground at the REAR WINDOW DEFOGGER relay socket.

    3. Refer to Circuit Testing .

  3. Turn ON the ignition, with the engine OFF.

Does the test lamp illuminate?

Go to Step 3

Go to Step 8

3

  1. Turn OFF the ignition.
  2. Test the control circuit of the REAR WINDOW DEFOGGER relay for a short to battery positive voltage and ground. Refer to Circuit Testing .

Did you find and correct the condition?

Go to Step 11

Go to Step 4

4

  1. Connect a test lamp between the BATT main 3 fused voltage supply circuit and the control circuit of the REAR WINDOW DEFOGGER relay socket.
  2. Turn ON the ignition, with the engine OFF.
  3. Using a scan tool, command the relay ON then OFF.

Does the test lamp turn ON and OFF?

Go to Step 6

Go to Step 5

5

Test the control circuit of the REAR WINDOW DEFOGGER relay for an open. Refer to Circuit Testing .

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 .

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 .

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 .

Did you complete the repair?

Go to Step 11

--

9

Replace the REAR WINDOW DEFOGGER relay. Refer to Relay Replacement .

Did you complete the replacement?

Go to Step 11

--

10

Replace the BCM. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 11

--

11
  1. Use the scan tool in order to clear the DTCs .
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

Go to Step 2

System OK