GM radio's question...
It is also compatible with 2000-up Camaro Monsoons. Assuming it is connected, and has CD's loaded, the TAPE/AUX (or CD/AUX if you have a 2000-up CD unit) button activates it when you press it a second time. Can't remember what buttons on the radio itself do what, but for the steering wheel controls, pushing "PLAY" does the same thing as the TAPE/AUX button. You can use "SEEK", up & down, to change tracks on the current CD. You can use "PRESET" to change to the next CD in the changer.
