GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Exterior Lights Schematics

1

Did you perform the Lighting System Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

Depress the brake pedal.

Do all of the stop lamps illuminate?

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

Go to Step 3

3

Is only one lamp inoperative?

Go to Step 9

Go to Step 4

4

  1. Disconnect the stop lamp switch.
  2. Connect a 15A fused jumper between the battery positive voltage circuit of the stop lamp switch and the signal circuit of the stop lamp switch at the stop lamp switch connector.

Do the stop lamps illuminate?

Go to Step 6

Go to Step 5

5

With a test lamp connected to a good ground, probe the stop lamp switch battery positive voltage supply circuit.

Does the test lamp illuminate?

Go to Step 7

Go to Step 8

6

Inspect the stop lamp switch adjustment. Refer to Stop Lamp Switch Adjustment in Hydraulic Brakes.

Did you find and correct the condition?

Go to Step 11

Go to Step 10

7

Repair an open or high resistance in the switched stop lamp circuit. Refer to Wiring Repairs or Connector Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 11

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8

Repair the open or high resistance in the stop lamp battery positive voltage supply circuit. Refer to Wiring Repairs or Connector Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 11

--

9

Repair the open or high resistance in the inoperative stop lamp power supply or ground circuit. Refer to Wiring Repairs or Connector Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 11

--

10

Replace the stop lamp switch. Refer to Stop Lamp Switch Replacement in Hydraulic Brakes.

Did you complete the replacement?

Go to Step 11

--

11

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3