i have a 2003 monte and i pulled out the stock cd player tried to put an aftermarket one in couldnt get it to work so i just put the stock cd player back in now the lights on the cd player light up but it doesnt turn on. no display lights show up either. any ideas?? thanks!

 

Maybe a blown radio fuse??? Check the passenger side fuse box, it's a 10a fuse IIRC. Shouldn't be anything other than that because I just put my factory deck back in my car after 3 months and it fired up just fine.

 

i had that same problem and it was the amp in the trunk was bad.. i had to rewire the car to put an aftermarket cd player in because the wire harness for the 01-05 monte carlos is like 90 bucks instead of the usual 15. hope that helped u out. if u want to keep the stock then just replace the amp in the trunk