GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Was the Brake Warning System Check performed?

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Go to Step 2

Hydraulic Brake Diagnostic System Check

2

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

Is the brake warning indicator on?

--

Go to Step 3

Go to Step 4

3

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

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 park brake warning switch. Refer to Parking Brake Indicator Switch Replacement .

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.
  2. If a short to ground does not exist, replace DRL module.

Is the repair complete?

--

Hydraulic Brake Diagnostic System Check

--

8

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

Is the brake pressure warning indicator on?

--

Go to Step 10

Go to Step 9

9

Replace brake pressure warning switch.

Is the repair complete?

--

--

10

  1. Reconnect brake pressure warning switch connector.
  2. Disconnect 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.
  2. If a short to ground does not exist, replace EBCM. Refer to Electronic Brake Control Module Replacement .

Is the repair complete?

--

Hydraulic Brake Diagnostic System Check

--

12

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

Is the repair complete?

--

Hydraulic Brake Diagnostic System Check

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