Axxess GMOS-09 OnStar Interface for Amplified GM Vehicles with "Door-n-Lock" Style Harness Designed to allow the user to require the OEM Radio with an aftermarket unit in amplified GM Vehicles with "Door-n-Lock" Style harness equipped vehicles with amplified audio system Retain full functionality of OnStar with adjustable volume output Retain warning and door chimes with adjustable level output Retention of Retained Accessory Power (RAP)convenience features Compatible with 2001-2003 Oldsmobile Aurora and 2000-2005 Pontiac Bonneville