GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The instrument panel cluster (IPC) illuminates the red brake warning indicator by supplying ground to the lamp. The EBCM sends a class 2 message to the IPC requesting illumination. The park brake switch is wired to the IPC logic. The red brake warning indicator also illuminates when the park brake is applied.

Step

Action

Yes

No

Schematic Reference: Brake Warning System Schematics and Instrument Cluster Schematics in Instrument Panel, Gages and Console

1

Did you perform the Hydraulic Brake Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Hydraulic Brakes

2

Verify a fault is present.

Does the system operate normally?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3

  1. Install a scan tool.
  2. Select the Instrument Panel Cluster Special Functions menu on the scan tool.
  3. Command all of the IPC indicator lamps On.

Does the brake warning indicator illuminate?

Go to Step 4

Go to Step 18

4

Apply the park brake.

Does the brake warning indicator illuminate?

Go to Step 5

Go to Step 6

5

  1. Disconnect the brake fluid level switch harness connector.
  2. Connect a fused jumper wire between the brake fluid level switch output circuit and the ground circuit of the brake fluid level switch. Refer to Using Fused Jumper Wires in Wiring Systems.

Does the brake warning indicator illuminate?

Go to Step 13

Go to Step 7

6

  1. Disconnect the park brake switch harness connector.
  2. Connect a fused jumper wire between the park brake switch output circuit and a good ground. Refer to Using Fused Jumper Wires in Wiring Systems.

Does the brake warning indicator illuminate?

Go to Step 11

Go to Step 8

7

Connect a fused jumper wire between the brake fluid level switch output circuit and a good ground. Refer to Using Fused Jumper Wires in Wiring Systems.

Does the brake warning indicator illuminate?

Go to Step 9

Go to Step 10

8

  1. Remove the IPC. Refer to Instrument Cluster Replacement in Instrument Panel, Gages, and Console.
  2. Test park brake switch output circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 19

Go to Step 17

9

Repair the open in the ground circuit of the brake fluid level switch. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 19

--

10

Test the brake fluid level switch input circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 19

Go to Step 15

11

Inspect for poor connections at the harness connector of the park brake switch. 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 19

Go to Step 12

12

Replace the park brake switch. Refer to Parking Brake Indicator Switch Replacement in Park Brake.

Did you complete the replacement?

Go to Step 19

--

13

Inspect for poor connections at the harness connector of the brake fluid level switch. 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 19

Go to Step 14

14

Replace the brake fluid level switch. Refer to Brake Fluid Level Indicator Switch Replacement .

Did you complete the replacement?

Go to Step 19

--

15

Inspect for poor connections at the harness connector of the EBCM. 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 19

Go to Step 16

16

Replace the EBCM. Refer to Electronic Brake Control Module Replacement in Antilock Brake System.

Did you complete the replacement?

Go to Step 19

--

17

Inspect for poor connections at the harness connector of the IPC. 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 19

Go to Step 18

18

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

Did you complete the replacement?

Go to Step 19

--

19

Verify the system is repaired.

Does the system operate normally?

System OK

Go to Step 3