GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

SCHEMATIC REFERENCE: Exterior Lights Schematics

1

Did you perform the Lighting System Diagnostic System Check?

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Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

Connect a test lamp between the stop lamp feed circuit at the stoplamp/auto trans shift lock control switch and a good ground.

Does the test lamp illuminate?

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Go to Step 3

Go to Step 5

3

  1. Connect a test lamp between the stoplamp switch output circuit at the stoplamp/auto trans shift lock control switch to ground.
  2. Depress the brake pedal.

Does the test lamp illuminate?

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Go to Step 4

Go to Step 6

4

Repair open in the stoplamp switch output circuit. Refer Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

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Go to Step 8

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5

Repair the open circuit or short to ground in the stoplamp feed circuit. Refer Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

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Go to Step 8

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6

Inspect of poor connections at the stoplamp/auto trans shift lock control switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

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Go to Step 8

Go to Step 7

7

Replace the stoplamp/auto trans shift lock switch. Refer to Stop Lamp Switch Replacement in Hydraulic Brakes.

Did you complete the replacement?

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Go to Step 8

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8

Operate the system in order to verify the repair.

Did you find and correct the condition?

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System OK

Go to Step 2