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 always on. Do the park, license, and tail lamps operate normally? | Go to Testing for Intermittent Conditions and Poor Connections | Go to Step 3
3 | Remove the park lamp relay. Refer to Relay Replacement . Do the park lamps turn OFF? | Go to Step 4 | Go to Step 9
4 |

1. Ensure that the headlamp switch is in the OFF or AUTO position and there is sufficient light to the ambient light sensor.
2. Test for a ground signal at the park lamp relay control circuit terminal in the underhood fuse block. Refer to Electrical Center Identification Views and Circuit Testing .

Was a ground signal present?

Go to Step 5

Go to Step 10

5 | Use the scan tool to check the body control module (BCM) Park Lamp Switch input data. Does the scan tool indicate a park lamps OFF request signal? | Go to Step 8 | Go to Step 6
6 | Test for a short to ground 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 13 | Go to Step 7
7 | 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 13 | Go to Step 11
8 | 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 13 | Go to Step 12
9 | Repair the short to voltage in one of the following circuits. Refer to Wiring Repairs :

• | The park lamp supply voltage

• | The tail lamp supply voltage

• | The license lamp supply voltage

• | The marker lamp supply voltage

Did you complete the repair?

Go to Step 13

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10 | Replace the park lamp relay. Refer to Relay Replacement . Did you complete the repair? | Go to Step 13 | --
11 | Replace the headlamp switch. Refer to Headlamp Switch Replacement . Did you complete the repair? | Go to Step 13 | --
12 | Replace the BCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 13 | --
13 |

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