I've been having this issue too, my right hand side speakers have all gone out at one time or another. (so much so that I had to replace them) I have not changed out any wiring or amps yet, that will be my winter project. I thought my Amp, RCA's, or speaker wire were causing the problem, but maybe its a bad RCA Channel (side) on the head unit. I've seen alot of "right side speakers not working" threads here...