Q: I am attempting to install a new after-market head unit into my '02 Nissan Xterra. I removed the stock head unit but when I went to plug in the new unit, it would never power up. I triple checked my wiring (used a harness) to make sure the red, yellow, and ground matched up. Still nothing. Next, I figured I would see if my original head unit would power on. I plugged that back in and now it won't power on either. I figured it might be a blown fuse. I checked the fuse on my new head unit. Looked good. Next, I checked my fuse box. I wasn't 100% which fuse matched the power to my unit. I figured it was most likely "Elec Assc". No blown fuse there either. To be sure, I took out every fuse in the fuse box and checked them. Nothing. Then I replaced the correct fuses back. Still nothing. I'm stumped. Any ideas of what could be wrong? Or how to run some further tests to get to the bottom of this? Also, I had the stock non-6 CD Changer headunit. No amp.
A: Try following the wires back. Sometimes there are many different connection on the wires for car stereos. Maybe something got disconnected along the line. Edit: oh, and try starting the car. The new harness might only allow the stereo to run while the car's ignition is on.