For 1990-2009 cars

Step | Action | Yes | No
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Schematic Reference: Exterior Lights Schematics Connector End View Reference: Lighting Systems Connector End Views , Automatic Transmission Related Connector End Views for the 4L60-E/4L65-E transmission, or Manual Transmission Connector End Views for the Aisin AR5 transmission
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle
2 |

1. Block the rear wheels.
2. Turn ON the ignition, with the engine OFF.
3. Place the gear selector in PARK or the shifter in Neutral.

Do the backup lamps illuminate?

Go to Step 3

Go to Testing for Intermittent Conditions and Poor Connections

3 | Disconnect the park/neutral position (PNP) switch, if equipped with a automatic transmission, or the backup lamp switch, if equipped with a manual transmission. Do the backup lamps remain illuminated? | Go to Step 4 | Go to Step 5
4 | Repair the short to battery positive voltage in the backup lamps supply voltage circuit. Refer to Circuit Testing and Wiring Repairs . Did you complete the repair? | Go to Step 6 | --
5 | Adjust or replace the PNP switch or backup lamp switch. Refer to Park/Neutral Position and Backup Lamp Switch Adjustment and Park/Neutral Position and Backup Lamp Switch Replacement for the 4L60-E/4L65-E transmission, or Backup Lamp Switch Replacement for the Aisin AR5 transmission.

Did you complete the repair?

Go to Step 6

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6 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 3