ok i just bought a 1994 ford F250, 5.8 ext cab ext bed dual tank. we had a problem with wiring and had to replace a bunch of wires, pos batt neg batt alternator wires and starter and starter solenoid wire. now when i turn on the headlights the truck dies and the battery doenst hold a charge. replaced the bad battery and it still doesnt hold a charge but will jump and run till you shut it off or turn on the headlights. any help would be appreciated or a wiring diagram of some kind. cause im at my wits end and have run out of ideas and money.

 

Something you might check,
There are at least 2 fusible links in the wires that come from the battery positive terminal to the starter relay on the firewall. Those links feed the fuse panel(s) that are in the vehicle. I believe you have a power distribution box under the hood and a fuse panel under the left side of the dash by the steering column.
I would suspect there is not enough juice getting to the panels since when you turn on the headlights it robs the ignition system of current.
The simple way to check those links is to tug on them and if they feel like an elastic band they are open.The only thing holding the wire together is the covering.
You can substitute a piece of regular wire in their place to confirm if they are open or not.
The temptation to just jump it with regular wire and forget it leaves the possibility for any excessive load to fry the wiring harness. Not a good idea.

Always a good idea to clean and coat the ground connections (all of them) .

 

ok ive replaced all the wiring, the battery holds a charge but still when you turn on the headlights the truck dies. the fuse box and distribution box wires have all checked out fine. im thinking i got a bad ground somewhere but im having troubles locating it. i get a little lost as most wires are compiled into a wiring harness. is there a way to get the exact wiring diagram for this truck in particular and not every type from 85 to 94? the part that bothers me the most is that in my ten years as a mechanic i have never seen this problem before and its really gonna bother me when i find out its something simple ive over looked or forgot about.

 

Don't feel bad, if what you say is correct, somebody has wires screwed up in the system.
This is what I would do,
Unplug both headlight sealed beams.
If the engine still cuts off you no longer have a bad ground for the headlights.
This can take some persistence because , are you ready for this,,,,,,, the headlite wiring goes through the flash to pass system in the smart stick that controls the sig lites and wipers. This can take a while to locate, but if you are willing to stick with it I will try to help and I don't even know just how much help I can be. So let's get going.
What happens with the headlites disconnected?

Grindman ,a participant on this forum, has a 94 Ford also and if he is reading this he may be able to provide wire color and location info.