OnStar backup battery [Archive] - Audi Forums

: OnStar backup battery

11-29-2009, 07:09 PM
Hey... Does anyone know where the backup battery for the OnStar system in a 2004 Audi A8L is located? Or any information on the subject? I ask because my status light is illuminated red, and the owners manual says the backup battery needs replacing. Just don't know where it's located or how to get at it. Any help would be appreciated. Thanks.