GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Exterior Lights Schematics

1

Did you review the Lighting System Description and Operation and perform the necessary inspections?

Go to Step 2

Go to Symptoms - Lighting Systems

2

Verify that the stop lamps are inoperative.

Does the system operate normally?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

  1. Apply pressure to the brake pedal, to activate the stop lamp switch.
  2. Test cavity 1 of the stop lamp switch for battery positive voltage.

Is voltage present?

Go to Step 4

Go to Step 7

4

  1. Connect a fused jumper wire on the stop lamp switch connector between cavity 2 and cavity 1.
  2. Test C4 cavity 5 of the instrument panel fuse block for battery positive voltage. Refer to Circuit Testing .

Is voltage present?

Go to Step 5

Go to Step 6

5

Test C5 cavity 7 of the instrument panel fuse block for battery positive voltage. Refer to Circuit Testing .

Is voltage present?

Go to Step 10

Go to Step 11

6

Repair the open in the stop lamp switch output voltage between the stop lamp switch cavity 1 and C4 cavity 5 of the instrument panel fuse block . Refer to Wiring Repairs .

Is the repair complete?

Go to Step 12

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7

Test cavity 2 of the stop lamp switch for battery positive voltage. Refer to Circuit Testing .

Does the test lamp illuminate?

Go to Step 8

Go to Step 9

8

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

Is the replacement complete?

Go to Step 12

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9

Repair the open in the battery positive voltage circuit between the stop lamp switch and C4 cavity 14 of the instrument panel fuse block. Refer to Wiring Repairs .

Did you complete the repair?

Go to Step 12

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10

Repair the open in the stop lamp supply voltage circuit between C5 cavity 7 of the instrument panel junction block and SP300. Refer to Wiring Repairs .

Is the repair complete?

Go to Step 12

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11

Replace the instrument panel wiring harness. Refer to Instrument Panel Wiring Harness Replacement .

Is the replacement complete?

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