What is the absolute basic wiring needed to start a 1980 F250? Swapping an intact 86 harness to my 80 butchered harness. All lights re-wired front and rear. Does anything from fuel tank (as far a electrical wiring goes) have to be connected to run? Original problem started after new heads and water pump installed at local shop. On the way home got a warning ticket for 3-4 foot flames shooting out the back of my truck every time I would turn on my lights....Truck would run fine, but would die when heater blower was turned on, or when headlights were turned on???

 

Power to

The ignition module
The ignition coil
The alternator(for it to charge)

To the solenoid so it will crank over.

 

You cannot just swap a newer 1981-1986 main wiring harness into the 1980 without swapping some of the parts with it.

The 1980 is wired totally different to the 1981-1986.

If you are trying to splice a 1986 main harness into your existing 1980 main harness, then you will have major compatibility issues. Very possibly the reasons for the issues you have quoted above.

You will also have to change the headlamp switch and instrument cluster as well, as these are 1980 only components. The fuse panel circut pathways are 1980 only... etc...


Headlamp Switch: 1980 Only
Headlamp Switch: 1981-1986

Instrument Cluster: 1980 Only
Instrument Cluster: 1981-1986

Fuse Panel Circuts: 1980 Only
Fuse Panel Circuts: 1981-1986

Hopefully you see a pattern there...

 

if i were you, i'd call up the shop that did your heads and tell them they screwed up your truck, and you want it fixed.

also, check your grounds all over the truck, especially the one from engine to body. bad grounds are the only way i can even start to explain weird things like that happening whenever you turn on any electrical accessory (lights, blower, etc).
the more i think about it, i bet they forgot the ground wire from engine to body. if you don't see one, add one or two, and make them heavy, 10ga or heavier.

 

Only used the wires in the original wiring loom... I Used existing harness and switches... My 1980 had a utility trailer wiring harness in back to allow for tail lights only. I spliced in the loom from the 1986 for lighting purposes only.. The front ungrounded side marker light wires were just cut and hanging, reverse lights cut, more like gone, license plate lights diddnt exist... No more FARM TRUCKS for me, its just another word for POS latlely...thanx for the input.. I will be focusing on ground wires and hope to resolve the problem... The service shop kinda shrugged it off, but they did offer to look it over during the next couple weeks when they weren't busy, no thanx...

 

well then i guess you're on your own. you might consider telling your local BBB (better business bearau) about the wonderful service and how well they stand behind their work