GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Did you perform the Diagnostic System Check?

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Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

  1. Turn the ignition to the RUN position.
  2. Depress the brake pedal.

Do all of the stop lamps illuminate?

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

Go to Step 3

3

  1. Connect a test lamp between the center high mounted stop lamp (CHMSL) terminal A and ground. Refer to Circuit Testing in Wiring Systems.
  2. Depress and hold the brake pedal.

Does the test lamp illuminate?

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Go to Step 4

Go to Step 5

4

  1. Connect a test lamp between the CHMSL terminal A and terminal B. Refer to Circuit Testing in Wiring Systems.
  2. Depress and hold the brake pedal.

Does the test lamp illuminate?

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Go to Step 6

Go to Step 7

5

Repair a poor connection or an open in the supply voltage circuit of the center high mounted stop lamp. Refer to Wiring Repairs or Connector Repairs in Wiring Systems.

Did you complete the repair?

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Go to Step 8

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6

Replace the CHMSL. Refer to one of the following procedures:

Did you complete the replacement?

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Go to Step 8

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7

Repair a poor connection or an open in the ground circuit of the center high mounted stop lamp. Refer to Wiring Repairs or Connector Repairs in Wiring Systems.

Did you complete the repair?

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Go to Step 8

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8

Operate the system in order to verify the repair.

Did you correct the condition?

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System OK

Go to Step 3