Windshield Wiper/Washer Signals to the BCM
WARNING: This page is about a different car, the 2008 Cadillac STS. However, it is still accessible from the selected car via links, so may be relevant.
The BCM receive two signals indicating the operation of windshield wipers and washer. The windshield wiper switch signal 2 circuit is used by the BCM to turn ON the headlamps. The windshield washer switch signal is used by BCM to control the headlamp washers.