Conditions for Setting the DTC
WARNING: This page is about a different car, the 2009 Pontiac Torrent and 2009 Chevrolet Equinox. However, it is still accessible from the selected car via links, so may be relevant.
DTC B3600 03 will set when the BCM detects a short to ground or an open/high resistance in the I/P dimmer switch signal circuit.