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 stoplamps 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 10

Go to Step 4

4

  1. Disconnect the stoplamp 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 stoplamps illuminate?

Go to Step 7

Go to Step 5

5

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

Does the test lamp illuminate?

Go to Step 6

Go to Step 9

6

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

Did you find and correct the condition?

Go to Step 13

Go to Step 8

7

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

Did you find and correct the condition?

Go to Step 13

Go to Step 12

8

Inspect for a poor connection at the harness connectors of the console fuse block. 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 13

Go to Step 11

9

Repair the open in the stoplamp battery positive voltage supply circuit. Refer to Wiring Repairs or Connector Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 13

--

10

Repair the open in the inoperative stoplamp power supply or ground circuit. Refer to Wiring Repairs or Connector Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 13

--

11

Replace the console fuse block. Refer to Console Electrical Center or Junction Block Replacement in Wiring Systems.

Did you complete the replacement?

Go to Step 13

--

12

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

Did you complete the replacement?

Go to Step 13

--

13

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3