Daytime Running Lamps (DRL) Inoperative. Chevrolet TrailBlazer

For 1990-2009 cars only

Makes 🢒 Chevrolet 🢒 2007 🢒 TrailBlazer - 4WD 🢒 Body Systems 🢒 Lighting 🢒 Daytime Running Lamps (DRL) Inoperative

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	Verify that the daytime running lamps (DRL) are inoperative. Do the DRL operate normally?	Go to Testing for Intermittent Conditions and Poor Connections	Go to Step 3
3	Do the low beam headlamps operate normally?	Go to Step 4	Go to Symptoms - Lighting Systems
4	Ensure that the park brake is not SET. Install a scan tool. Turn ON the ignition, with the engine OFF. With a scan tool, observe the Park Brake Switch parameter in the body control module (BCM) data list. Does the scan tool display RELEASED?	Go to Step 6	Go to Step 5
5	Test the signal circuit of the park brake switch for a short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct a condition?	Go to Step 12	Go to Step 8
6	Remove the headlamp driver module (HDM). Install a test lamp between the headlamp driver module connector battery positive voltage circuit terminal and the headlamp driver module control circuit terminal. Refer to Circuit Testing . Use the scan tool to command the DRL ON while observing the test lamp. Does the test lamp illuminate at slightly less than full intensity?	Go to Step 11	Go to Step 7
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 12	Go to Step 9
8	Inspect for poor connections at the harness connector of the park brake switch. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?	Go to Step 12	Go to Step 10
9	Replace the BCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement?	Go to Step 12	--
10	Replace the park brake switch. Refer to Parking Brake Indicator Switch Replacement . Did you complete the replacement?	Go to Step 12	--
11	Replace the HDM. Refer to Relay Replacement . Did you complete the replacement?	Go to Step 12	--
12	Use the scan tool in order to clear any induced DTCs. Operate the system in order to verify the repair. Did you correct the condition?	System OK	Go to Step 3