Did you disconnect the RCA cables(I asked before but you did not respond)?Did the car have a Bose system? Or was it the factory Nissan amp? Was the amp bypassed(all speakers wired directly)? What is the manufacturer of the cd player? Some manufacturers have a 'safety' mode that cuts the amp off if a short is detected. I think dave97lx could be right about them hooking the wrong wire up to the remote turn on. I say you disconnect the amp from the car(all the wires off it and taped up) and go from there. Worst case is the the internal amp in the cd player is blown.