Generator Battery Disconnect Control Module

WARNING: This page is about a different car, the 2007 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.

The generator battery disconnect control module, sometimes referred to as the battery disconnect unit (BDU) or battery energy control module (BECM), is a serviceable GMLAN device which is mounted to the rear of the generator battery carrier assembly. This controller also includes several non-serviceable sub-components, including a current sensor, service disconnect switch and the 36-volt system contactor. The generator battery disconnect control module controls the generator battery vent fan and monitors temperature, voltage and current levels within the generator battery. The service disconnect switch attached to the controller is a plunger type switch used to open the 36-volt system contactor during service activities. The switches plunger rests against the generator battery disconnect control module cover, and it closes when the cover is closed and opens when the cover is opened. The 36-volt system contactor will open and close in conjunction with the service disconnect switch. When the contactor is in an open position, the generator battery will be electrically isolated from the vehicle, although intermediate voltage potential will still be present within the generator battery carrier assembly and the generator battery disconnect control module.