Circuit Description
WARNING: This page is about a different car, the 2005 Chevrolet Malibu. However, it is still accessible from the selected car via links, so may be relevant.
The body control module (BCM) monitors the ACCESSORY signal from the ignition switch. When the vehicle operator places the ignition switch in the Accessory or Run position, the switch supplies B+ to the BCM ACCESSORY input terminal. If this circuit becomes shorted to B+, ground or the circuit opens, DTC B1380 will set.