Headlamps Inoperative - High Beams

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: Headlights/Daytime Running Lights (DRL) 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	Place the headlamp switch in the ON position. Place the dimmer switch in the high beam position. Do the high beam headlamps operate normally?	Go to Testing for Intermittent Conditions and Poor Connections	Go to Step 3
3	Is only one high beam headlamp inoperative?	Go to Step 4	Go to Step 5
4	Test the high beam headlamp supply voltage circuit for high resistance, an open or a short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?	Go to Step 15	Go to Step 8
5	Place the headlamp switch in the HEAD position. Place the headlamp dimmer switch in the high beam position. With a scan tool, monitor the High Beam Relay Command data parameter in the body control module (BCM) data list. Does the scan tool display On?	Go to Step 13	Go to Step 6
6	Test the headlamp dimmer switch signal and ground circuits for an open or high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct a condition?	Go to Step 15	Go to Step 7
7	Place the headlamp switch in the HEAD position. Connect a fused jumper from ground to the headlamp dimmer switch signal terminal of the headlamp dimmer switch connector. Do the high beam headlamps illuminate?	Go to Step 9	Go to Step 10
8	Inspect for poor connections at the harness connector of the inoperative bulb. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition?	Go to Step 15	Go to Step 11
9	Inspect for poor connections at the harness connector of the headlamp dimmer switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition?	Go to Step 15	Go to Step 14
10	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 15	Go to Step 12
11	Replace the high beam bulb. Refer to Headlamp Bulb Replacement (Cadillac) or Headlamp Bulb Replacement (Tahoe, Avalanche) or Headlamp Bulb Replacement (Yukon) . Did you complete the replacement?	Go to Step 15	-
12	Replace the BCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement?	Go to Step 15	-
13	Replace the underhood fuse block. Refer to Underhood Electrical Center or Junction Block Replacement . Did you complete the replacement?	Go to Step 15	-
14	Replace the headlamp dimmer switch. Refer to Turn Signal Multifunction Switch Replacement . Did you complete the repair?	Go to Step 15	-
15	Operate the system in order to verify the repair. Did you correct the condition?	System OK	Go to Step 3