The GM20SR is a plug and play interface that allows replacmenet og a GM Class II factory stereo in Cadillac CTS and SRX vehicles. It will maintain operation of the OnStar® and factory amplified systems. The GM20SR has on board switching to allow audio from the OnStar® system to play through thte two front factory Speakers when OnStar® is active. It also retains warning chimes for OnStar® operation. For additional vehicle integration, use Scosche's line of SWC-1 steering wheel controls (SWC) interface to retain steering wheel controls with the aftermarketing radio. Also retains Vehicle Parking Assist Chimes.
2003-2007 Cadillac CTS
2004-2007 SRX *Not compatible factory navigation
Note: The GM20SR does not retain the factory XM receiver
Why do I need an interface?
An interface is a small computer system that allows your new head unit to properly communicate with your vehicle’s computer system. If you install a new aftermarket radio without using an interface, you will lose many of the standard security features of the vehicle. This is due to vehicle manufactures running part of the vehicle’s computer system through the OEM radio. Functions lost include, but not limited to, are warning chimes (keys left in ignition, lights left on, low fuel etc.), security and alarm systems, +12V accessory and more. If the +12V accessory is lost, your radio will not turn on/off automatically and will be a manual process.