Can't be a ground problem, as the brake lights share that ground, and they work.
A $3 test light will tell you if it's getting power or not.
I could photocopy our shop manual wiring diagram here at Ford if that would help a little...but simply having a diagram won't help much to most lay people.
I adjusted a distributor once on a fine running 4.9 Ford based solely on the pulley marks...which were off a whole bunch due to the balancer portion slipping. It idled ok enough, but the drive home had it running really hot with very little power, and fuel gauge dropping rapidly over 40 miles...
First post here...gotta say that i really, really like MikeRuth's sofa/bed combo. Simple, elegant, functional, and room underneath for some long RC airplane wings. :)