First, Thanks everyone for all the help. So I have a 1986 F350 6.9. The truck is creeping up to 400k so I imagined I'd have trouble like this before too long. Just the other day, I had driven my truck to work, and a couple hours later I had to leave the lot to go on a parts run. I drove about 30 feet and then the truck just died. And I don't mean it stalled out, I mean that EVERYTHING went dead. Engine, radio, all dash instruments, even my headlights wouldn't come on. I monkeyed around and checked everything. Cleaned my grounds, tried to trace the wires as best as I could on the side of the road, broke out the volt meter and all, to no avail. Eventually, I gave up and just ran a hot wire to my fuel pump, IP, and jumped the glow plug controller and starter sol., and drove it 30 minutes home. It ran fine all the way, but I had no instruments or lights. Any ideas or leads that someone could point me too? I've already done some digging and checked what other people seem to describe as general problem areas in the wiring harness, but all of those connections are good. I'm really depending on this truck and I don't have a lot of time to spend looking for a needle in the haystack while I'm trying to balance full time work and college and home life. Thanks a bunch Y'all.

 

I had the same thing happen on my 82 F250 300 six and it was a relay going to the solenoid if I recall correctly. It's more than likely a relay in the beginning of the electrical line somewhere....

 

Did you jump the starter SOLENOID (ON the starter) or the starter RELAY (on the fender)?

Unless you or a previous owner has modified the truck, you don't have a hot wire on your fuel pump. It's mechanical. If indeed it's an electric fuel pump, what other mods does the truck have that haven't been disclosed?

Check for voltage at each battery, at the always-hot terminal of the glow plug relay, and at the always-hot terminal of the starter relay. Not sure about your '86, but technically, the original wiring layout on my '85 had the main power to the truck going from the passenger-side positive to the glow plug always-hot terminal, and THEN a wire from there to the always-hot starter relay terminal. Then all the accessories (fuse links) ran from that terminal on the starter relay out to the rest of the truck. Somewhere along the lines, they switched to running the main wire from the battery + to the starter relay terminal, which then acted as the junction to the accessories and to the GP relay. Electrically, it works out to be the same, but the wire tracing and chasing down the bad connection will be different. You'll just have to follow wires to see which way yours is wired, and check all those connections while you're at it.

When you ran the jumpers to emergency start the truck, did any of the accessories (exterior lights, etc) work?

 

Thanks for the info! Yes, I put an inline fuel pump in and blocked off the mechanical pump. Sorry. I should have mentioned that. And I jumped the starter from the fender. And yes, I checked for power going past the gp controller and all. And even with the emergency wiring I did, I had no other power anywhere in the truck. No headlights, turn signals, or dash instruments: oil pressure, temp gauge, or even voltage gauge. Its all dead. The though crossed my mind that maybe it was my ignition switch. However, I can't even get my headlights to turn on, which runs independant from the ignition. It literally has no power whatsoever. But, from what I can tell, the problem is not under the hood but under the dash is my best guess. Because I think I checked the wires under the hood good enough to determine their working condition. However, I am not dead set in that theory. Its got to be just one point that all the power runs through, because for EVERYTHING to go dead all at once would be too much of a coincidence if it were multiple bad wires/connections. Especially since I dont even have power to my headlights. Again, thanks for the info! Its greatly appreciated.

 

All the "wires" on the always-hot terminal on the starter relay are actually fusible links. It's possible one or all of them have burned out. They feed pretty-much everything in the fuse box. That would be the next thing to check.

 

Thanks Mad, sorry that is what it was on mine a fusible link. I mean no nothing notta power.

 

if the wiring is stock all power for every thing comes from the large post at start solenoid on fender pass side, three large wires and the battery cable, 1 is the charge wire from alt, 1 is the main feed to glow plugs, 1 is the main feed to cab, all are fused with inline fusible links, they burn internally when they go out. that's the place to start....

 

It is almost certainly a blown fusible link by the starter relay, BUT when repairing it you must find out why it blew in the first place or it will happen again and second it is not ok to bypass a fusible link even temporarily lest you start an electrical fire. I dont mean to be an alarmist but I have set enough things on fire due to my own ignorance I dont want anyone else to have to learn that lesson the hard way! hope this helps

 

Thanks! And when I did the emergency wiring, I made sure that nothing else was energized. ONLY the ip and the fuel pump. If I can hunt down whats causing the problem, I will certainly repair it correctly. This truck has been too good to me for me to not treat it right. Thanks again! I'll see what happens when I dig around.

 

He has a C6 tranny or stick, what happens with a newer electronic controlled E4OD if you drive with no power ? Will it go into gear but not shift correctly ?

 

^^^^^ Probably. You could jump power to the TCM, I reckon. 'Course, it would be prudent to jump power to the brake pedal switch as well....

 

So a C6 is definitely better for a Road Warrior zombie mobile ?

 

^^^^ Better than an E4Oh$#!+, yes. Not better than a T19 / ZF5. Roll-start a manual truck and you can just about run it off a 9-volt battery.

 

Just pull the IP cover off and pull the little FSS lever out. Now, you can run it with /no/ battery! Killing it is harder, though(You can either kill it by letting out the clutch in high gear, or adjust the throttle idle down until it dies, then put a removable stop to keep it normally idling again. Yes, I've given some thought to all this).

 

So a C6 is a better tranny than a E4OD, I have a 89 7.3 with a C6 and a Gear Vendors OD. I take it that is good ?
Also I have guy here locally who is supposed to build a really mean E4OD or great Ford Auto's..... but they are PRICEY!