Well I just moved to Layton from Phoenix about a month ago. The reserve unit I worked for down there shut down and I put in for Hill. Anyways I needed a truck and wasn't really looking but while out looking for some ideas for a house I noticed a late 70's Ford f250 4x4 for sale. I drove by a couple times and finally stopped. Anyways I bought it this last Monday. It's a 76 f250 hiboy. It had a couple issues with it that i'm trying to sort out. The turn signals didn't work and neither did the brake lights or hazards. I bought a new turn signal/hazard switch hoping that would fix it. Well the turn signals work but not the brakes or hazards. I'm going to get the test light out and start trouble shooting tomorrow. Is there a wirring schematic that I can view online? Thanks.
Check the wiring under the tail gate area. Alot of times, folks will tap in trailer lights and bugger up the wires under there.
Also, I strongly suggest you post on the 73-79 forums. Mil1on is a member that sometimes frequents there and he has a huge amount of knowhow on these old highboys.
BTW, I've got a 74 F250 4x4. Best damned trucks ever built IMO.
Good luck finding the wiring problem.
I got all the lighting fixed on it. The turn signal switch in the steering column was shot along with a blown fuse. Next thing on the list is to get the electric choke working, pick up a new power steering return line, and get the front wheel bearings repacked. After that stuff i'll start working on cleaning it up and getting the rusty areas fixed or maybe a new bed.