GM has cleverly designed in a lot of tricks to force you to go back to the dealer and this is one of them. '94 models is the last year they allowed us to buy radio service manuals. They want all the repair business for their two grossly-overpriced repair centers. First the dealer will have to figure out if it's the radio or the remote amplifier that's quitting, then they have to remove it and ship it out for repair. The typical repair charge will total around $400.00 with all the shipping, reinstallation, and diagnostic charges. Be thankful you don't have a newer model. Most of them have to be programmed to the car, (and they don't do that for free), and now they're building the Body Computer into it so you can't even replace it with an aftermarket radio.