Owners of 2006-2011 Buick Lucerne vehicles may complain that the battery goes dead when the vehicle is parked. Battery electrical drain/parasitic load testing may reveal an abnormally high current draw that is traced to the F12 BCM LOGIC fuse (2006-2007 models), BCN fuse 19 (2008 models) and BCM fuse 32 (2009-2011) located in the rear fuse block. The problem may seem intermittent.
1. One cause could be a short to ground on circuit 1732. With the interior lights off, measure resistance to ground using an ohm meter on the BCM inadvertent power circuit. It may be necessary to manipulate the body harness while testing to reveal intermittent concerns. There should be no conductive path to ground on circuit 1732 with the interior lights off. If a conductive path to ground is detected, the short must be located. Likely locations for circuit 1732 to become shorted are:
Another cause could be the glove box light staying on intermittently. Inspect the glove box switch for proper depression. Temperature differences and customer loading may cause excessive clearance between the door and switch. A piece of small plastic tubing added to the plunger, or a riser pad may be added to the door to reduce the excessive clearance.