Diagnostic Aids

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Test the fog lamp switch for sticking in the ON position.
Perform a visual inspection for loose or poor connections at all related components. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

DTC B2527 Diagnostic Test

Step	Action	Yes	No
Schematic Reference: Fog Lights Schematics Connector End View Reference: Lighting Systems Connector End Views or Body Control System Connector End Views in Body Control System
1	Did you perform the Lighting Systems Diagnostic System Check?	Go to Step 2	Go to Diagnostic System Check - Lighting Systems
2	Install a scan tool. Turn ON the ignition, with the engine OFF. With a scan tool, observe the front fog lamp switch parameter in the body control module (BCM) data list. Does the scan tool display OFF?	Go to Step 3	Go to Step 4
3	Activate the front fog lamp switch. With the scan tool, observe the front fog lamp switch data parameter. Does the front fog lamp switch data parameter change state?	Go to Diagnostic Aids	Go to Step 4
4	Turn OFF the ignition. Disconnect the front fog lamp switch. Turn ON the ignition, with the engine OFF. With a scan tool, observe the front fog lamp switch data parameter. Does the scan tool display OFF?	Go to Step 7	Go to Step 5
5	Test the signal circuit of the front fog lamp switch for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 10	Go to Step 6
6	Inspect for poor connections at the harness connector of the BCM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 10	Go to Step 8
7	Inspect for poor connections at the harness connector of the front fog lamp switch. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 10	Go to Step 9
8	IMPORTANT: Perform the setup procedure for the BCM. Replace the BCM. Refer to Body Control Module Replacement in Body Control System.Did you complete the replacement?	Go to Step 10	-
9	Replace the front fog lamp switch. Refer to Headlamp Switch Replacement . Did you complete the replacement?	Go to Step 10	-
10	Use the scan tool in order to clear the DTCs. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text. Does the DTC reset?	Go to Step 2	System OK