This started a few week ago. Sometimes while driving, if I turned on the lights, radio, or heater, the truck would die or shudder and loose power then kick back on. It had always reset and continued driving as though no problem.

Then occasionally, after driving and stopping, shutting down engine and doing an errand or something, it would be completely dead and no power, I'd pop the hood wiggle wires around the inner fender solenoid and voltage regulator and power returned, truck started fine and no problems. Nothing appeared loose, disconnected, frayed etc...

Until yesterday... truck was running, idling while I was out checking my well pump house, I jumped back in it turned on the heater and truck died... no power anywhere, no power to key, lights, starter, etc...The jiggle the wires trick no luck, let it sit over night and still no power again this morning.

Batteries have plenty of power, I suspected a solenoid (inner fender) was bad and did the crossing of poles with a screw driver and starter turns over strong. Oddly, only the emergency flashers work, loud, appear correct flashing speed and whether ignition turned on or not as they are supposed to.

It is not in a place where I can get easily towed ouy of to try a roll start either. I'll be blocking the road if no luck starting.


I have no tools for checking voltage but truck always read midway and above on idiot light gauge for battery, system appears to be charging correctly when running and no other issues with electrical system has come up.


I'm going to auto parts store and I guess I'm going to replace the 2 small solenoids on inner fender and do I need to replace the silver square box (voltage regulator?) that says "short circuit protected... MOTORCRAFT" on it? I have to get a lift to the parts house so I can't make numerous trips.


My plan was to start replacing one part at a time and see what happens...

Help help help and advice is appreciated. I'm no real mechanic but I can usually figure it out. Is this a stupid question?
Thanks,
JB

 

That's the starter RELAY on the inner fender. The SOLENOID is on the starter.

On the horizontal surface of the wheel well is the glow plug relay. It's electrically COMPLETELY different from the starter relay; it just looks similar.

But before throwing parts at it, it will cost you LESS than any one of those parts to buy a cheap multimeter, so you can start TESTING. If jumping the starter relay cranked the engine, and you had the key in the RUN position at the time and it still didn't start, you have other problems. Esp. if other accessories are inop. FIRST thing to check is the fusible links coming off the power junction point on the starter relay. Those feed main power to the ignition switch, fuse box, etc.

You may also have a grounding problem. Grounds on these trucks are notoriously bad; it's why, for example, the alternator puts out almost zero charge until you rev it up. The voltage regulator grounds through its mounting to the wheel well; make sure that's clean and rust-free. Check main battery cables and positive and negative terminals/posts, and where the battery negative wires ground to the engine block.

Before this complete failure, when you said you could get it going by "jiggling some wires", which wires in particular?

 

Just a wild guess, but try this: Fire the truck up, then SLOWLY turn the key back and forth. Not enough to turn the truck off or to bump the starter again, but just up the built-in detents. Do this with the headlights, radio, HVAC, and other stuff on. See if anything weird happens, like the radio turning off or the truck dying.

The reason I say this is because I was having intermittent issues where the radio or HVAC would randomly stop working. It was very intermittent, so I never bothered troubleshooting it. One day it acted up again, so I couldn't turn on the defroster. I went to turn it off, and as I slowly turned the key, the HVAC suddenly came on. I replaced the tumbler (it was a newish unit, but a cheap aftermarket from the parts store) with an OEM tumbler, and I've had no issues since.

Just a thought,

Mike

 

you have bad connections, either at the battery, positive connect on fender mount starter relay, or a bad ground on the block. my money is on a loose ground wire or extremely dirty battery terminals.

 

I went to part store before replies were posted but thishas happened.
I first replaced the voltage regulator, plugged it in & screwed it down and the hood light came on, the interior light came on when I opened the door so I was thinking that was it but then I turned the key to start position and it all went dead again. No power anywhere.
The voltage regulator has "short circuit protected" written on top. I heard a click when the truck went dead. Could the voltage regulator have fried?
Do I now try replacing the starter relay or do I try something else?
Thanks

 

Check the fusible link, was having this issue in our 90 before we figured it out.

 

Sorry but what, where is the "fusible link"?
I'm about a mile from the truck and have no internet away from my house so I have to go back and forth, checking for replies and trying something else each trip. I may be able to tow it back tonight when my neighbor gets home and have easier trial and error attempts.

 

check the battery connections and grounds.
something is not making a connection, and when you try to draw power it is loosing the connection.

 

The fusible links are "wires" that supply power to all the electrical components on the truck (except the starter main motor). All those terminals attached to the power junction terminal on the starter relay, those are actually fusible links. They're designed to act like fuses, whereby if there's too much current flowing through the circuit, the conductor will burn up internally.

Just to clarify (and a visual inspection will make it even more obvious), that terminal on the starter relay is the junction point for power distribution to EVERYTHING on the truck, but it's JUST a junction point. One of those ring terminals is to a wire that comes from the passenger-side battery positive, and all the others go to the various circuits in the fuse box and some other under-hood components. If you follow it, it becomes evident that the relay itself has NO function for all this. Even if the relay were bad, all the things attached to that terminal would still be connected to the battery, and would still work. So the starter relay is probably NOT the culprit here.

Besides, the starter relay, along with everything else electrical on the truck, can easily be tested before just replacing it blindly. You're at the point now where you cannot meaningfully troubleshoot the problem(s) without even a cheap multimeter. It will pay for itself with just this issue, by helping you pinpoint what needs to be repaired or replaced, so you can avoid randomly throwing parts at the truck.

That said, when you have at least some accessories and components working initially, but then everything "goes dark" when you turn the key to START, that's _typically_ an indicator of a bad main power connection somewhere. In a nutshell, the weak connection is able to provide power to small/moderate loads like the interior light, etc., but when you nail it with a large load like the starter motor, the weak connection can't provide the power, and the attempt to do so pulls the voltage down abruptly. This kills the power to the other components that were working up until then. Typically, messing with the main cables or even disconnecting and reconnecting the batteries restores the connection (still weak) to the small load components, but if you try to start it again, the same thing happens.

In fact, thinking it through, this suggests to me that your starter relay is GOOD. If it were inop, the starter would never be triggered to try to pull that much power, and you wouldn't have that "everything went dark" effect.

One other thing to consider investing in, although the payoff is not as immediate as with the cheap multimeter, is an EVTM - Electrical / Vacuum Troubleshooting Manual. It's a full book of wiring diagrams for the truck, including main power distribution, fuse assignments, all switches/relays, insulation colors of all the wires, connector pinouts, etc.

And yes, getting it towed to a more convenient location will be very useful.

 

got it started... still don't know what is wrong? Jiggled the wiring harness with all the wires to the new voltage regulator and it came back to life. I guess I have to unwrap the covering and loom to try to find the short. Can't see any loose connections on anything, starter relay, VR, batteries, etc

 

you have to take a wrench to all the connections to ensure they are tight.

 

And just because they're tight doesn't mean there isn't corrosion causing a poor connection.

 

Look: Right now, hotwire it:
1. You already know how to crank the engine.
2. You need power to the FSS solenoid. Run a wire from Battery+ to here:

https://www.ford-trucks.com/user_gal...d=132028&.jpg=
3. As the GPs won't work(unless they're clicking, in which case ignore), grab some starting fluid and spray about a 1s stream into the air cleaner. Crank with the throttle about 1/4 way down until it fires. If it dies, repeat.

This should get you on your way. Remove the line to the FSS to kill the motor(and prevent the battery from draining).

Then, grab a multi-meter and start going over everything later, when you have time. If you need it for a DD, just run some bypass wires(from battery+ into cab to a switch, then to the FSS).