first ive never done it in a grand prix but i have taken gm windshield wiper motors apart and had success cleaning them and getting them to work...there is also a pin and set of gears that sometimes come out of alingment...bend the pin toward the gears so they make better contact and sometimes that helps...if not buy a new one....second our radios and all gm radios with cd players are known for their problems...just get an aftermarket