I have an 84 F150 4.9 4x4. I've had battery drain issues for the past two months. Took the negative cable off the battery and hooked a test light up to the negative post and the negatvie cable and the light came on. So I know i have juice feeding back through my negatvie cable. Have unplugged to voltage regulator and the light stays lit. Took the nut off the battery side soleniod post and removed the wires one by one. There are two wires with fusable links going into one connector thar slides over that soleniod post when I unhook it the light goes off. So I went to the inside of the truck and pulled the fuses one by one while looking through the windshield at the test light. The light never went off. So I replaced the 28 year old alternator and put another voltage regulator on it that I had laying around. Still having the same problem. Just been unhooking the negative post on the battery when I park the truck. I have traced the two fusable link wires fron the solenoid to the inside of the truck. I have found a replacement wiring harness including fusebox and some other accesories. before i bite the bullet and buy the new harness I was gonna see what you guys thought.

 

I doubt its wiring, I'm not sure what runs off of those fusible links. There are wiring diagrams at AutoZone.com that may help you.

 

Can you tell what color the wires with the fusible links are? Or, are there any identification #'s? I have wiring diagrams for the 81's and suspect they'll be much the same as yours.

EDIT: There is usually one color wire between the solenoid and the fusible link, and another after the link. For instance, one is red ahead of the link but black-orange after. If you can figure that out I think we can nail where the wires go. Or, I can copy this page if need be.

 

it is two wires both with the links going into one connector sliding over the solenoid post. one turns to black with orange stripe the other turns solid yellow found them in the dash when they run up and over the guage pod and again as they feed 12v power to the back of the fuse box. came up 2 inches from fuse box cut both wires left enough to butt connect them back together. Without being hooked up to fuse box they still cause the light to come on between the negative post and cable so apparently indicating a short between the solenoid and the fusebox.

 

In my schematics there is a black/orange and a yellow wire that come together onto one connector and go on the solenoid. The black/orange of this pair goes into the headlamp switch to provide constant power. The yellow goes into the ignition switch. So, neither should be drawing any power if the lights are off and the ignition is off. But, the headlamp switches are notorious for having problems, so you might want to pull yours to see if there are melted wires on it.

However, there are several black/orange and several yellow wires coming from the solenoid via fusible links. The difference is the color of the wire going into the link. Can you figure that out on yours? Otherwise, you may have cut the wrong wires.

 

Pulled the dash out today. The yellow has another fuseable link on the left side of the instrument panel as does the black/orange. The yellow splits into three wires, two going to plunger swith for the ignition mounted on top of steering column the other to the fusebox. The black orange splits one goes to headlamp switch one goes to fuse box. Unplugged headlamp swith test light on battery went off. But the headlamp swith only has a short when the lights are on. My problem was going on all the time. Considering the price of the headlamp switch I am going to buy a new one and hook overything i can back up without reassembling the whole dash and see what happens whether it still has the short or not.

 

That's the only way to figure it out - one step at a time and backtrack when that doesn't work. But, it is worth it in the end when everything works properly and the battery stays charged. Keep on keeping on.

 

Update: Put in new headlamp switch this morning and reassembled the dash after everysingle thing I hooked up i would go around with the test light on the battery again and check to see if the short came back. got it completely assembled and no short. Truck runs which is amazing considering the God forsaken cluster of wires there was to deal with. Now onto my blinkers which have recently gone out. Hazard flashers work front and back but the blinkers come on and keep a constant stream of power and do not flash. The Hazards do flash but the blinkers stay lit front and back. Has been an issue for a couple of weeks now. Whats the solution to this?

 

Well, welcome to my club of TSFOSB. (Two Steps Forward, One Step Back)

But, your steps forward were big ones and the step back is small. Four things come to mind re the turn signals:

1. Bad flasher module: Did you swap with the hazards?
2. Not enough current, like one bulb is bad. But, you said "front and rear" so apparently both are lighting. However, someone once put the wrong bulb in one of my trucks and the flasher wouldn't flash but the lights came on. However, they would have had to do both sides to get what you are seeing.
3. Bad ground: If you have a bad ground the current will go through other bulbs to ground, such as the tail lights, and the combination doesn't pull enough current so the flashers don't flash.
4. Bad wiring. Kinda doubt it on your truck (), but it might be a possibility. In this case it might be that the circuit doesn't go through the flasher. So, pull it and see if that kills the lights.

 

Got off work this morning and put a new module and new bulbs in and it fixed the problem. Thanks for the help. Leaving for Afghanistan in December and when I get home I am going to restore the truck. My dad and I took two trucks and built this one so I am gonna do a complete frame off on it. Looking forward to tearing into it and making the truck better than new.

 

Actually, the thanks goes to you for serving our country. But, glad you got it fixed.