Nissan Repair: Shorted tail lamp/instrument panel, tail lamps, aftermarket stereo

Question
2002 Pathfinder SE

i installed an aftermarket stereo and now my tail lamps are shorted and my instrument panel isn't working.  It happens when I connect the "illumination" wire and when I don't.  I also have an interface (PAC) that connects the steering wheel controls to an IR signal to act as a remote control.  How do I locate this short and how do I fix it? THANKS!!!!!!!!!!

Answer
Perry,

take the wires loose that you installed with the radio and especially the ground.  The wire you are tied to does both power and ground and the power is reversing.  Get a test lite if you want to verify.  But, Nissan does some strange things with radios and isolated grounds.  Wire the radio directly to the fuesblock and your problem should go away.