Whoa!! Funny I ran across this thread... I'm in the middle of installing a new headunit into my 1990 Eddie Bauer Bronco II. I tore the old headunit out and was disappointed at how small the wires were that were "going to the speakers." Then I realized that there was a wire to turn on an external amp, and it actually went somewhere on the truck. So I began thinking hmmm... Surely there's not really an amp in this truck??
But then I started pulling the speakers out to replace them with the Sony xPlod ones I got. And lo and behold, the wires are bigger at the speakers! So this thing did have an amp!! And now by chance I read this thread tonight and it confirms my theory!
I never really figured that my little standard ol' Bronco II had an Amp. Figured Ford would be too cheap to do something like that!
So can anyone give a more detailed description of where the amp is hidden? And also, is there any advice out there with regards to wiring a new headunit into this amp? What kinda output does this thing provide? Truthfully, I always thought the standard sound system was pretty good sounding, especially when I took into consideration its almost 20 years old.
I also pulled the factory speakers out, and they're in perfect shape, in fact they're 2 way speakers from the factory! In a 1990 BII! I was amazed. Of course their condition might be due to the fact that my Grandfather owned it from 1991-June 2009, and only listened to history cassette tapes on the Civil war with the thing... It probably never went above 25% volume in the entire 17 years he had it.

But hey, what can I say...Ford quality at work right there!

lol