For 1990-2009 cars

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: Exterior Lights Schematics Connector End View Reference: Lighting Systems Connector End Views or Data Communication Connector End Views
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle
2 | Verify that the park, license, and tail lamps are inoperative. Do the park, license, and tail lamps operate normally? | Go to Testing for Intermittent Conditions and Poor Connections | Go to Step 3
3 |

1. Remove the park lamp relay. Refer to Relay Replacement .
2. Ensure that the headlamp switch is in the ON position.
3. Test for a ground signal at the park lamp relay control circuit terminal in the underhood fuse block. Refer to Circuit Testing and Electrical Center Identification Views .

Was a ground signal present?

Go to Step 8

Go to Step 4

4 | Use the scan tool to check the body control module (BCM) park lamp switch input data. Does the scan tool indicate a park lamps ON request signal? | Go to Step 7 | Go to Step 5
5 | Test for an open or high resistance in the park lamp switch on signal circuit. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 11 | Go to Step 6
6 | Inspect for poor connections at the harness connector of the headlamp and panel dimmer switch. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 11 | Go to Step 9
7 | Inspect for poor connections at the harness connector of the BCM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 11 | Go to Step 10
8 | Replace the park lamp relay. Refer to Relay Replacement . Did you complete the repair? | Go to Step 11 | --
9 | Replace the headlamp switch. Refer to Headlamp Switch Replacement . Did you complete the repair? | Go to Step 11 | --
10 | Replace the BCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 11 | --
11 |

1. Use the scan tool in order to clear any induced DTCs.
2. Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3