Car Audio System in a 90 LX V8 stang convertible
 

I have a 1990 LX V8 convetible.
First off Here is my dilema I went to install a deck and used a common wire harness kit that I purchased from tweeters. Only when I pluged it in there was no sound. I tested the deck on a speaker that I had our of the car and it worked. I looked at the wires in the stang and realized that only 5 wires running in to the stang 4 positves and 1 negative I assume. So the wire harness i bought isn't working. Any ideas besides running new speaker wire? Perhaps I have an amp from the factory? If so where is located? I got the car a few months ago and really haven't had a chance to rip it apart and put it back together. This is my 3rd stang all the others were easy to run a harness into.
Second off I plan on putting a sub in my convertibles trunk. Yes it sounds silly i know. But I have done it in the past and it doesn't sound half bad for the HUGE sacrafice of trunk space. I was just wondering if anyone has any suggetions. I use a truck box and put it on the left side of my trunk.
Lastly if i need to rewire all my speakers has anyone run speakers wires in a convertible? If so any suggetions? Doesn't sound to inticing but the things i do for sound. I already attempted to pull the speakers from the door unsucesfully. I unscrewed every screw but i couldn't pull them. Any ideas?
Oh just a few more questions. How hard is it to get to the speakers in the dash(are they some how bridged to the wires going to the door)? How does one get the back seat out(i forgot how)? Does anyone have any suggetions that might help please let me know they will be greatly appreciated?
Basically any suggetions will be appreciated!

Is your car the anniversary edition? Mine was (also premium sound package) and it used european style wiring (aka common ground wiring). I had to re-wire all the speakers. If you have the premium sound package, then you will have a separate amp...if you take out the deck you will see it underneath... Just looks like a small grey box.

P.S. another fun thing to check is the ohm rating for the deck. The stock speakers are 2 ohm. Most decks put out 4 ohms. If you have 6 speakers and hook them all up, don't expect the deck to last long. What you can do, is hook four of em up and get some 4 ohm tweeters.

But most of this is only applicable if you have the premium sound system (six speakers + amp)

Thanks,
DoranW

I installed it all:
Pioneer 3000 sereies cd player with dual pre-amp outputs
PPI speakers all around
the 3.5 off the head unit
the 6.5 and 5x7 off a Power Accoustic amp 4 channel 600 watts peak 300 rms (just a little too much power)
I'm running a MTX 8104A 10 inch sub(don't buy one I blew it way to quick cause of the small truck box I use) powered by another Power Accoustic amp 2 channels 200 rms 400 peak. I'm thinking JL audio W-3?
For anyone doing a system in a drop top stang it is a *****.. I ran the RCA's down the Passanger side of the stang and the Power down the drivers side. I didn't pull my back seat out to run the wires to the truck. Rather I ran them in the intereior pannel that the rear speakers are in not that hard to do just unscrew all the screws and pull it all throudh. Now for the really complicated part I ran all the wires into the smallest space possible. A small gap between the seat pannel on the side and the convertible pannel. It took me a good half hour to run everything. Then I just ran it under the vinyl boot and through the 2 pieces of carpeting in the trunk. (What a *****) Oh and then I ran wires to the 5x7s and 6.5s the same way. Don't attempt this unless you have a good 8 hours to blow one day. I had a semi profesinal installer helping me do all this. If I were to do it all again I would run conpnets and put the tweeters on a custom fabricated mount in the dash where the 3.5s go!
As for the sub and the amps I put the amps under the roof where there is a gap for the glass from the top I belive. I have never removed the glass and the space is way too small for anything but books and bottes of alcohol anyways. So we built a cutom amp rack and it looks clean. In extreme emergencies i disconnect everything and get to my spare if I absolutely must. The tuck box slips right in and can be removed when i need some space in my joke of a truck That is why there is a luggage rack anyways right?
If anyone has any questions drop me an email. I'm not an expert but I'm on my 3 rd stang and I might be able to help!