OS-2C

• OnStar Compatible: The interface retains your vehicle's factory OnStar system. It allows audio from the OnStar system to play through the vehicle's two front speakers when OnStar is active, and mutes the output of your new aftermarket radio.
• Factory Amplifier: The PAC radio replacement interface lets you retain your vehicle's Standard or Bose factory amplifier. Due to the design of the factory amplified system, there is currently no way of fading from the front to rear with an aftermarket radio.
• RAP: Your aftermarket head unit will continue to operate with the vehicle's RAP (Retained Accessory Power) system. The aftermarket radio will stay on after the vehicle's key is turned off and then stays on for approximately 10 minutes or until a door is opened.
• Safety & Warning Chimes: The vehicle's factory safety and warning chimes are also fully retained.

PAC OS-2C-CTSX Wiring Interface owner's manual