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 back up lamps are always on.

Does the system operate normally?

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

Go to Step 3

3

  1. Disconnect the park/neutral position (PNP) switch.
  2. Shift the transaxle to the PARK position.
  3. Turn the ignition switch to the ON position.

Do the backup lamps illuminate?

Go to Step 4

Go to Step 5

4

Adjust/replace the park/neutral position switch. Refer to Park/Neutral Position Switch Replacement in Automatic Transmission - 35 Speed - MB3.

Did you complete the repair?

Go to Step 8

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5

  1. Disconnect the backup lamp switch.
  2. Shift the transaxle to the NEUTRAL position.
  3. Turn the ignition switch to the ON position.

Do the backup lamps illuminate?

Go to Step 6

Go to Step 7

6

Replace the backup lamp switch. Refer to Backup Lamp Switch Replacement .

Did you complete the repair?

Go to Step 8

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7

Repair a short to B+ on the backup lamp feed circuit between the backup lamp switch and the SP450. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 8

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8

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3