Sounds like a bad connection , The amp on the radio is going into protect, but that doesnt shut off the output of the rca's.So thats why your sub plays but the highs dont . If you put the radio in, make sure all connections are good, and that there is no strands of wire that could be touching metal or another speaker wire behind the deck . If thats all good , then you could have a poor connection at one of the speakers, or possible a bad speaker . Try disconnecting 1 at atime and see if you can get it to shut off when you hit a pothole or whatever. usually if its a factory connection and no one has ever touched it or spliced it, they usually dont go bad. Try tat and let us know what you have found.