i have a 99 montana. it recently developed a problem with the factory stereo for no apparent reason. it wont eject cds. none of the buttons on the deck work. if you turn the volume knob the stereo shuts on and off. the steering wheel controls work intermittently. i have had no look figuring this out. can anyone here help?

Does the radio work?

My '95 Bonneville stereo had the same problem with the CD not ejecting. Started once-in-awhile when new (and just out of warranty;-). Now it takes a few days to a couple months to eject. I've liked w-it 9 years since stereo otherwise is great. My suggestion is to have it replaced - - a used unit "w-warranty" should cost less than $199 through dealer. Or try eBay (with warranty) etc. Some others outlets have much $higher prices too, so shop around.

My bet is it's much more costly to repair given all your other symptons - see estimates at link http://carstereohelp.com/pontiac.htm. This sites is also good for general info (http://carstereohelp.com) as well as others like it http://www.delco-radio-repair.com/. Also check out forums to learn & get pointers from others (such as www.gmpower.net/forums/)