GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Exterior Lights Schematics

Connector End View Reference: Lighting Systems Connector End Views

1

Did you perform the Lighting Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

Depress the brake pedal.

Does the system operate normally?

Go to Testing for Electrical Intermittents in Wiring Systems

Go to Step 3

3

Disconnect the stop lamp switch.

Do the brake lamps go out?

Go to Step 7

Go to Step 4

4

Remove the CHMSL fuse.

Do the brake lamps go out?

Go to Step 9

Go to Step 5

5

Test the stop lamp switch signal circuit of the turn/hazard flasher module for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 12

Go to Step 6

6

Test the left and right stop/turn lamp supply voltage circuits of the turn/hazard flasher module for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 12

Go to Step 8

7

Inspect for poor connections at the harness connector of the switch. 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 12

Go to Step 10

8

Inspect for poor connections at the harness connector of the turn/hazard flasher module. 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 12

Go to Step 11

9

Repair the short to voltage in the CHMSL supply voltage circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 12

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10

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

Did you complete the replacement?

Go to Step 12

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11

Replace the turn/hazard flasher module. Refer to Hazard and Turn Signal Flasher Replacement .

Did you complete the replacement?

Go to Step 12

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12

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3