Park, License, and Tail Lamps Always On

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2007 GMC Yukon XL, 2007 GMC Yukon, 2007 Chevrolet Tahoe, 2007 Chevrolet Suburban, and 2007 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.

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 and reinstall each park lamp fuse one at a time. Do all of the park lamps turn OFF when a particular fuse is removed?	Go to Step 9	Go to Step 4
4	Ensure that the headlamp switch is in the AUTO position and there is sufficient light to the ambient light sensor. With a scan tool, monitor the Park Lamp Relay Command in the body control module (BCM) data list. Does the scan tool display Off?	Go to Step 5	Go to Step 10
5	Use the scan tool to check the BCM park lamp switch input data. Does the scan tool display Inactive?	Go to Step 8	Go to Step 6
6	Test for a short to ground in the park lamp switch signal circuit. Refer to Circuit Testing 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 switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector 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 Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition?	Go to Step 13	Go to Step 12
9	Repair the short to voltage in the affected park lamp supply voltage circuit. Refer to Wiring Repairs . Did you complete the repair?	Go to Step 13	-
10	Replace the underhood fuse block. Refer to Underhood Electrical Center or Junction Block 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	Operate the system in order to verify the repair. Did you correct the condition?	System OK	Go to Step 3