I've been on this thing for over 2 hours now, tring to find a wiring diagram to a 1985 6 cylinder F150
I knew I could go by a $30 Manual, Aa Duu, No one Knows of a Site that has free Downloads for this.... Watta waste of Time
I picked up a 85 F150 Xcab, with a 5.8 HO.
Just found out this truck came with a 300 6 cylinder
so the color codes arn't matchin up.
For instance a Yellow fuse link wire fron the solinois Pos. side is Burnt out where did that Go? I have NO Horn How's that get wired, Ect. Ect.
Different engines won't affect much on the colors and functions of most of the wiring for the chassis/body. That wire you are talking about over at the solenoid + is the same no matter what engine. That's the main power wire and is shown in this diagram. http://repairguide.autozone.com/znet...3f80212308.gif
In the middle of the diagram there is a wire that says "To starter relay" and is a yellow wire that leads to the ignition switch.
The same diagram has a wire leading from the steering column area that says "To horn switch". I know it's not much. If I were you I would get a haynes from the store and see if they still have the diagrams in the back of them for these trucks. They are usually pretty good and onyl around $19 or so, and you get a lot of other info on the driveline and the body.
Do you have cruise or not? If you have cruise, you have a horn relay, and the button on the steering wheel grounds the wire to make it activate the relay and send power to the horn. If you do not have cruise, then the horn button is a simple switch that sends power directly to the horn with no relay. The first thing I would do is find the horn, and put power to it to see if it works.