GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Was the Brake Warning System Check performed?

--

Go to Step 2

Hydraulic Brake Diagnostic System Check

2

  1. Disconnect the daytime running lamp module (DRL) connector.
  2. Place the ignition in the RUN position.

Is the brake warning indicator on?

--

Go to Step 3

Go to Step 4

3

Locate and repair the short to ground in CKT 33 (TAN/WHT) between the instrument cluster and the DRL connector. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Hydraulic Brake Diagnostic System Check

--

4

  1. Reconnect the DRL connector.
  2. Disconnect the park brake warning switch.

Is the brake warning indicator on?

--

Go to Step 6

Go to Step 5

5

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

Is the repair complete?

--

Hydraulic Brake Diagnostic System Check

--

6

Disconnect connector C100.

Is the brake warning indicator on?

--

Go to Step 8

Go to Step 7

7

  1. Inspect for a short to ground in CKT 33 (TAN/WHT) or CKT 1134 (LT BLU). Refer to Wiring Repairs in Wiring Systems.
  2. If a short to ground does not exist, replace the DRL module.

Is the repair complete?

--

Hydraulic Brake Diagnostic System Check

--

8

  1. Reconnect connector C100.
  2. Disconnect the brake pressure warning switch.

Is the brake pressure warning indicator on?

--

Go to Step 10

Go to Step 9

9

Replace the brake pressure warning switch.

Is the repair complete?

--

--

10

  1. Reconnect the brake pressure warning switch connector.
  2. Disconnect the electronic brake control module (EBCM) connector C1.

Is the brake warning indicator on?

--

Go to Step 12

Go to Step 11

11

  1. Inspect for a short to ground in CKT 680 (PPL). Refer to Wiring Repairs in Wiring Systems.
  2. If a short to ground does not exist, replace the EBCM. Refer to Electronic Brake Control Module Replacement in Antilock Brake System.

Is the repair complete?

--

Hydraulic Brake Diagnostic System Check

--

12

Locate and repair the short to ground in CKT 33 (TAN/WHT) between the EBCM connector C1 and C100. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Hydraulic Brake Diagnostic System Check

--