Radio Wiring

[rahjah]

I just picked up a 1992 s13 and I am trying to install my Alpine head unit out of my other vehicle in the 240. I purchased the wiring harness and connected all of the wires according to the color coded instructions. Upon plugging in the head unit I can hear what appears to be the speakers getting power, they pop a little bit, but the head unit will not power on. It worked fine in my 4Runner and the head unit that was in the 240 worked when the previous owner removed it. I have done the wiring twice and checked all of the fuses and nothing. I am sure that someone else has dealt with this and I hope they are here and can help me. Thanks in advance!