2nd Gen Non-Engine/Transmission Radio problems

[CHamer]

I have a 97 3500 and all at once my radio started going of and on. It might go off for 2 or 3 minutes and then come back on,or it may go off and on every 5 seconds then all at once work fine for a day or two. I checked all the connections and I could not get it to do this with the trucked parked and shaking wires, like it may be a bad connection. It just does this when I'm driving. Has anyone else had this problem, if so how did you fix it.