[90limited]

I know that I could get a better CD head unit than factory, but I wanted the 7up car to look stock... That said, the electric side of things was a breeze (plug and play). The downside is I cannot figure out how to wire the speakers. My 1990 has 5 wires going to the amp from the head unit out of the long black eight pins in a row plug on the car harness. The 1996 CD head unit (F4TF-18C815-AC) uses the more squarish plug that is two rows of four.

Both the factory unit that came in the car and the CD unit are premium (need an amp). Anybody have any ideas.

[90limited]

OK more info... the newer cd head unit has a line level out for four speakers +- to the amp, which is 8 wires. The amp in the 1990 car has five wires, a common ground and 4 other wires for the individual channels. Can I connect one or all of the grounds from the head unit to the one ground input on the amp?

[2BADSTANGS]

The simple answer is yes, you can. However you need to be sure that the original had a line level output and not a speaker level output. It will not hurt anything to plug the new sterio in to test it, you will just barely hear any sound if the original was speaker level. If that dosn't work, get an amp and harness out of a '93 premium sound car (some other years may have them, but I am sure the '93's did.). They use the square amp feed plug. I have the whole amp/ wiring setup if you need one.