Hi gang! H>E>L>P... I've had this truck since new...been around the block several times with electrical issues, but this one has got me. To lay some foundation I have replaced and/ or maintained all electrical items recently and in the past. [113k orig. miles]

The truck was running well up to 2 weeks ago. While idling at the end of a 15 min. drive, just stalled out, all electrical dead. I mean everything, lights radio, everything. After sitting 3 min, started up and ran fine.
After that first incident, was fine untill yesterday got home from work, parked in drive, idling then dead again. Had, dinner, went out and truck started, warmed up for 3 min, and died[all electrics dead again] This time completely dead a no second chances for dtarting or getting any electricals!

[just now did the following] I have a new battery[I load tested it, cleaned all terminals at the starter and frame ground. Put in a New ignition switch [ electrical switch down colum under dash, not key switcth]
Fuse box is dead, checked for broken wire behind box/ harness...headlights dead everything dead.
Checked fusible links at wires comming off batt+ cable at starter switch, both hot BEFORE/AFTER fussible links] [There is a thick orange black wire with fussible link in same area that I think is a ground...checked it with test light connected to + cable and this wire lit up the test light BEFORE/AFTER the link, guess it is ok?
Could it be the computer [orig] even with the headlights dead? The TFI module and coil are newer replacements[motorcraft] NEED HELP FOR SURE!

 

You need to stay out at the starter solenoid large + terminal. This is how it generally goes;

There is a large wire going from the battery + to the large terminal on the solenoid. Under the large terminal on the solenoid is some smaller wires. These are the ones with the fusible links, and this one point is where all the electrical for the whole truck is fed.

I believe you mentioned you where checking fusible links in the solenoid + area, you need to check them again. After the fusible links at the + on the solenoid, it will go out and you will run into splices, one to the alternator, and then you may hit some more down the line, one should be the headlights, and another will be a yellow that feeds the ignition switch and then the fuse box. Your problem is going to be out on the pass side fender in all this major power feed section with fusible links and splices. Unwrap the harness if you have to, and keep probing the wires.

One other area it could be; Check the ground wire going from one of the bellhousing bolts to the firewall and see if it's ok.

 

Thanks very much for the info and tips Franklin! I'm going outside to try to get her running today. I forgot to mention that a few years ago I had terrible corrosion to all the connectors of these wires that sit on the pas. side wheel well at the solnoid/Map sensor area. I had spliced all the wires and eliminated all the connectors there. I checked the splices and they all look sound. Wiring diagram shows a "hot all the time" Yellow wire. and that orange/black wire. I imagine I'll leave the light switch and Key to the on positions while checking. As I follow the harness to the driver side wheel well There are about 4-5 big connectors there. I had sealed them up with some battery terminal protector, and they "look" sound. I'll try to post back the outcome this eve.

LATTER THIS EVENING...FOUND THE PROBLEM- Ammeter gauge [add on aftermarket] was burned out!. I noticed the needle was stuck in the voltage side of 0. Both terminals of the gauge should be hot, but only one was. I by-passed the gauge connections and truck came back to life!

 

That's a good idea to leave some loads on the circuits, so you get good readings with the meter while testing.

 

LATTER THIS EVENING...FOUND THE PROBLEM- Ammeter gauge [add on aftermarket] was burned out!. I noticed the needle was stuck in the - amp side of 0. Both terminals of the gauge should be hot, but only one was. I by-passed the gauge connections and truck came back to life!

 

Not to rain on your parade, but the fact that bypassing the ammeter brought the truck back to life is concerning. The truck should work just fine with the ammeter gone, assuming a shunt-style ammeter.

If the ammeter was open-circuit and the truck was dead, and bypassing the ammeter solved the problem, then it almost sounds like all of your truck's power is being fed through the ammeter. That makes it sound like you still have blown fusible links, and the ammeter was installed upstream of the links (bad).

You mentioned the ammeter was aftermarket, which suggests it could have been installed incorrectly. However, you also said the needle pointed to the "voltage side of zero," what does that mean? Ammeters measure current, not voltage. There is no "voltage side." A voltmeter measures voltage. What do you have? If you have a voltmeter, then things are wired differently.

Either way, if bypassing the wiring behind an aftermarket gauge is the difference between the truck being alive and no power at all, then something else is going on and requires further investigation.

 

It sounds like he has a aftermarket ammeter, and if he does, then yes all the power goes through this gauge and if it went bad it would kill the truck. That's why you have to be careful wiring up this type of gauge. It usually uses a unfused wire directly off the battery that runs through the firewall to the ammeter, and then back out to the tie point for the truck's power. If your wiring practices are poor, it's a good place to start a fire. Also if you use substandard wiring(too small) then you have too much voltage drop through this ammeter wiring and the whole vehicle's performance suffers.

 

Good to know, thanks for the clarification. I had just assumed it was a shunt-style ammeter like the factory. Another reason not to use an ammeter IMO.

 

The origional factory charge/discharge gauge failed several years ago. Bought a sun-pro aftermarket ammeter[they were made here in Cleveland, OH USA] Lasted 15 years. I Disconnected it and reconnected origional wiring before splicing in the sun-pro gauge. In other words, truck is as was from new, with a dead but unaltered factory gauge.

 

The factory ammeter gauges rarely worked, even when new. If you are worried about monitoring your charging system, I would get a voltmeter and install it instead.