The speaker wires will not make any difference if the polarity (+ and -) is reversed. If it were the case, it would still make sound, just be out of phase. Simply put it seems that you have a stereo that is designed for whatever your truck isn't. If your truck has an amp, that stereo is made for a car\truck that doesn't have an amp. If your truck doesn't have an amp, then your stereo is built to have an amp. It also appears that at the time your specific truck came out, they used one stereo regardless on if you had an amp or not (well, the plug is there, but who knows about the amp internals). I would really look into a newer deck, you can get something that support mp3\SD\USB (my favorite) so relatively cheap, and you'll be about to fit 40+ full CDs on a USB drive, without the possibility of skipping, ever. On top of that, newer head unit not only produce more power, but it much cleaner (Total Harmonic Distortion). I was shocked at the fact, but I have Alpine Type R components that are typically power hogs, and when I got my Kenwood Excallon XDC-K891, the Head Unit powers them fantastically. Don't get me wrong, its not as good as it could be, but it's waaay better than I expected. Just my $.02

 

work truck, i just want fm radio. Thats it.

 

Ah, well that stereo might not do the trick...

 

Yes, polarity matters on some Fords because of how the radio & speakers are grounded. But it's easy to repin the connector as needed.

 

I tried to repin, but didnt have much luck

 

Steve I emailed you about the radio, did you get it?

 

Thats strange, on my 89 it wasn't anything special, just a normal 2 pin set up, maybe something changed after my year. I did have the lowest of the low quality speakers\radio ford had to offer lol (Grandfather was around before music was invented so he doesn't like it)