GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Exterior Lights Schematics

1

Did you review the Exterior Lighting Systems 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 in Wiring Systems

Go to Step 3

3

Test for battery voltage at terminal 1 of the stop lamp switch.

Is battery voltage present?

Go to Step 5

Go to Step 4

4

Repair the open in the battery positive voltage between the stop lamp switch and S241. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

Go to Step 10

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5

Test for battery voltage at terminal 2 (M/T) or terminal 3 (A/T, M/T w/cruise) of the stop lamp switch.

Is battery voltage present with the brake pedal depressed?

Go to Step 7

Go to Step 6

6

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

Is the repair complete?

Go to Step 10

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7

  1. Disconnect C205.
  2. Test for battery voltage at terminal 9 with the brake pedal depressed.

Is battery voltage present?

Go to Step 9

Go to Step 8

8

Repair the open in the stop lamp voltage supply circuit between the stop lamp switch and C205. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

Go to Step 10

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9

Repair the open in the stop lamp voltage supply circuit between the C205 and S304. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

Go to Step 10

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10

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3