GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The park brake control module illuminates the APPLY PARK BRAKE indicator when the ignition is OFF and the parking brake is released. The PBCM illuminates the indicator by supplying voltage to the lamp.

Diagnostic Aids

Thoroughly inspect connections or circuitry that may cause an intermittent malfunction. Refer to the following:

    •  Testing for Electrical Intermittents
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs
    •  Connector Repairs

Test Description

The number below refers to the step number on the diagnostic table.

  1. The PBCM may be damaged if the apply park brake indicator control circuit is shorted to ground.

Step

Action

Yes

No

Schematic Reference: Park Brake System Schematics

1

Did you perform the Parking Brake Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Park Brake

2

  1. Release the parking brake.
  2. Turn OFF the ignition.

Does the APPLY PARK BRAKE indicator turn ON?

Go to Diagnostic Aids

Go to Step 3

3

  1. Disconnect from the instrument panel cluster, the harness connector containing the apply park brake indicator control circuit. Refer to Instrument Cluster Replacement in Instrument Panel, Gages, and Console.
  2. Connect a test lamp between the apply park brake indicator control circuit and a good ground.

Does the test lamp illuminate?

Go to Step 4

Go to Step 5

4

Inspect the apply park brake indicator lamp for an open filament.

Did you find and correct the condition?

Go to Step 11

Go to Step 7

5

Disconnect from the PBCM, the harness connector containing the apply park brake indicator control circuit. Test the apply park brake indicator control circuit for an open or a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 6

6

Test the ignition 1 voltage circuit for a short to voltage. Refer to Circuit Testing and Wiring 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 instrument panel cluster. 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 8

8

Replace the instrument panel cluster. Refer to Instrument Cluster Replacement in Instrument Panel, Gages, and Console.

Did you complete the replacement?

Go to Step 11

--

9

Inspect for poor connections at the harness connector of the PBCM. 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

10

Replace the PBCM. Refer to Park Brake Control Module Replacement .

Did you complete the replacement?

Go to Step 11

--

11

Ensure that the parking brake is released and that the ignition is OFF.

Does the APPLY PARK BRAKE indicator turn ON?

System OK

Go to Step 3