So does anyone know of where i can get the wiring diagrams for my 1990 f350 7.3? cause the dimer switch isnt working this is the second one. the head lights come on but not the parking lights. the first time it happen the pigtail that was hook up to it was melted and burnt so i thought that was it well guess not it did it again but didnt melt it this time just dont work now. so if anyone know whats up or has a idea im all eyes. thanks

 

I had all sorts of headlight switch problems with my 89 Super Duty. Local Ford parts manager stated frequent problems with those era switches. I converted to a toggle switch--had to do a bit of experimenting to get the wiring correctly connected. Good luck.

 

yea its blowing the fuse and found that my hazard light fuse or what ever it is the spot it goes in is fried along with a few wires but still no fix.

 

Shorting wire(s) some place. My truck has a junction box at the rear that connects truck flat bed and trailer lights. Had a hot wire that shorted with exposed turn signal wire, causing strange problems. If you have trailer connection, I'd start there and work back, looking for exposed wires. Good luck.

 

sorry it took me so long to message back. i found where it was one of the lights on my driver side was shorting out. but the guy that put the bed on my truck he used house wiring and whatever he could find i guess. but thats another day to figure that out. so far doing without wire diagram for my truck... thanks for the post i will look and see if i can find if its got that.