GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Hydraulic Brake Schematics

1

Did you review the brake warning system circuit description and perform the necessary inspections?

Go to Step 2

Go to Symptoms - Hydraulic Brakes

2

With the ignition switch ON, observe the brake warning indicator and perform a brake warning system test by meeting each of the conditions described in the circuit description.

Did the brake indicator illuminate for each condition?

Go to Testing for Electrical Intermittents

Go to Step 3

3

Is the brake indicator completely inoperative in all conditions?

Go to Step 18

Go to Step 4

4

Did the brake indicator illuminate with the float manually held down?

Go to Step 5

Go to Step 7

5

Did the brake indicator illuminate with the parking brake applied?

Go to Step 6

Go to Step 10

6

Did the brake indicator illuminate with the ignition switch in START?

Go to Testing for Electrical Intermittents

Go to Step 15

7

  1. Disconnect the brake fluid level switch connector.
  2. Connect a 3 amp fused jumper wire between the brake indicator control circuit and the ground circuit.
  3. Turn ON the ignition switch.

Does the brake indicator illuminate?

Go to Step 8

Go to Step 9

8

Replace the brake fluid reservoir which contains the fluid level switch. Refer to Master Cylinder Reservoir Replacement .

Did you complete the repair?

Go to Step 19

--

9

Test the ground circuit of the brake fluid level switch for an open. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 19

Go to Step 17

10

  1. Disconnect the park brake switch connector.
  2. Connect a 3 amp fused jumper wire between the park brake signal circuit and chassis ground.
  3. Turn ON the ignition switch.

Does the brake indicator illuminate?

Go to Step 11

Go to Step 12

11

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

Did you complete the repair?

Go to Step 19

--

12

  1. Disconnect the DRL control module connector.
  2. Connect a 3 amp fused jumper wire between the brake indicator control circuit and chassis ground.
  3. Turn ON the ignition switch.

Does the brake indicator illuminate?

Go to Step 13

Go to Step 17

13

Test the park brake signal circuit for an open. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 19

Go to Step 14

14

Replace the DRL control module. Refer to Daytime Running Lights (DRL) Control Module Replacement .

Did you complete the repair?

Go to Step 19

--

15

  1. Disconnect connector C203.
  2. Test the ignition switch for continuity in the START position. Refer to Circuit Testing and Wiring Repairs .

Is the circuit continuous?

Go to Step 17

Go to Step 16

16

Replace the ignition switch. Refer to Ignition and Start Switch Replacement .

Did you complete the repair?

Go to Step 19

--

17

Test the control circuit of the brake indicator for an open. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 19

Go to Step 18

18

Replace the instrument cluster Refer to Instrument Cluster Replacement .

Did you complete the replacement?

Go to Step 19

--

19

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3