doing something like that you may need to use a test light to find out which one is you battery positive and your switched power (ignition) use a walkman or some thing to find out which ones are the speakers (only do this after you find your two power wires above) (sometimes Fords will only have one negative wire for all the speakers,it is shared by all speakers, but each speaker will have its own positive wire) so on a 4 speaker system you may have only a total of 5 speaker wires! That is not always the case though. if it is then a lot of the times the gray wire is the shared negative. usually you have the ground wire located by the time you have your speakers figured out, if not then hook your test light up to your battery positive wire and touch a bolt or some thing with it to make sure that you have good contact on the positive wire then touch any remaining wire(s) that you have not identified and when you get the ground, your light will come on....hope this helps
