GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

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

Disconnect the stoplamp/auto trans shift lock control switch connector.

Did the stoplamps turn off?

--

Go to Step 4

Go to Step 3

3

Repair short to battery positive voltage in the stoplamp/auto trans shift lock control switch load circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 5

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4

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

Did you complete the replacement?

--

Go to Step 5

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5

Operate the system in order to verify the repair.

Did you find and correct the condition?

--

System OK

Go to Step 2