GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

1

Attempt to operate the vehicle courtesy lamps and the power door locks.

Are the courtesy lamps and power door locks operational?

Go to Step 2

Go to Body Control Module Inoperative in Body Control Systems

2

Check for body control module (BCM) DTCs. Refer to Diagnostic Trouble Code (DTC) Displaying in Body Control Systems.

Does the BCM sound and flash DTC 7?

Go to DTC 7 Horn

Go to Step 3

3

Does the BCM display or sound any other DTCs?

Go to Diagnostic Trouble Code (DTC) List/Type in Body Control Systems

Go to Symptoms - Horns