What caused this electrical carnage?

[HammerDown]

Here I thought the GP Controller went bad... nope (wasted $200)
So, did the existing bad connection at the multi-pin connector cause the two wires going into the eyelet to burn-up or, did something in the fender mounted starter relay fail and burn wires?
My continuity tester well tell if any of the fusible links are fried... if not, I'll get a new multi pin connector and put wires back in a new eyelet.
Wish I saw all that carnage before spending $200 on a new GP Controller.
Question... why are those wires for the eyelets going to the fender relay so thick and insulated? They all bolt together on the same stud.

 

[ROCK HARVEY]

My bet would be the multi-pin connector as the point of failure. That’s where mine failed too.

 

[Clb]

Most often burnt wires = Bad Grounds .
And poped fuses are loose or faulty wires.

 

[ROCK HARVEY]

I think those two yellow wires that feed the glow plugs are pretty notorious for failing at that connector. They see a lot of amps, and they’re only 10 gauge. Add some corrosion and those pins heat up like they’re glow plugs.

 

[Nero]

Mine sort of melted the same connector, causing intermittent no glow plug operation. I ended up cutting the wires and bypassing the connector completely. Been fine since then. I'd imagine it's because it's not a weather sealed connector, so moisture gets in there and just wrecks it.

 

[gandalf]

I think its a common problem. I simply cut the yellow cables, and powered the glow plug controller from another source.

 

[HammerDown]

I think those two yellow wires that feed the glow plugs are pretty notorious for failing at that connector. They see a lot of amps, and they’re only 10 gauge. Add some corrosion and those pins heat up like they’re glow plugs.

Yep... I may cut them back and tie-in heaver gauge male/female bullet connectors. They'll be a new connection, clean and shrink wrapped etc.

 

[HammerDown]

My bet would be the multi-pin connector as the point of failure. That’s where mine failed too.

Question... when yours fried did it hurt the fender mounted starter relay?
I'd hate to make everything 'pretty' and have a bad starter relay hurt something else.
My engine cranks fine but obviously no GP's because of the burnt wires.

 

[IDIBRONCO]

Even though it's not the clearest picture, you can see that my wires are still fine. A few years back, I sprayed some WD-40 on one side of the plug. Then I plugged it in and unplugged it several times. I blew both sides out with air and put some dielectric grease on the pins before plugging them back together. It's probably about time for me to do that again. I feel that everyone who still has good wires at this plug should do the same if they want to keep the factory plug.

 

[HammerDown]

Even though it's not the clearest picture, you can see that my wires are still fine. A few years back, I sprayed some WD-40 on one side of the plug. Then I plugged it in and unplugged it several times. I blew both sides out with air and put some dielectric grease on the pins before plugging them back together. It's probably about time for me to do that again. I feel that everyone who still has good wires at this plug should do the same if they want to keep the factory plug.

Don't think I recognize that plug...where's it at?

 

[david85]

I'm 99% sure it was the plug.

The only corrosion protection the plug has, is some kind of grease that's applied at the factory. It works surprisingly well but after 30 years, it will eventually get corroded. These plastic, unsealed connectors will all fail eventually, unless you do something like IDI Bronco and add some kind of fresh grease, oil, anything. We're often scared to pull these apart because of how brittle they can get. But this is the result when they are left to fester.

My glow plug wires had been bypassed for over 10 years but the other day after changing the injectors, the ignition wire decided to let out the magic smoke right before my eyes while the truck was idling. Only the fuse wire burned up thankfully. Now the entire plug is bypassed.

Note that on older trucks the plug is generally grey. Bricknose trucks tend to be black. I'm not sure what color OBS trucks have, but all the harnesses will have the connector on the passenger side of the engine, near the dipstick (but a few inches closer to the wheel well).

 

[IDIBRONCO]

I'm 99% sure it was the plug.

It is. That's the way it looks on my 1985.

 

[ROCK HARVEY]

My plan is to upgrade to 6 gauge wires and use this connector:

HYCLAT 6-10 Gauge Battery Quick Connect/Disconnect Wire Harness Plug Connector Recovery Winch Trailer, Pack of 2, Red https://a.co/d/6aRG4F9

 

[IDIBRONCO]

That should work. I'd still put some dielectric grease on the contacts. That stuff is almost like a miracle.

 

[Rdnck84_03]

Don't think I recognize that plug...where's it at?

It is in the general area of the passenger valve cover, a/c box are. I don't remember exactly where it lands at because I have that harness rolled up and zip tied out of the way just in case I want to go back factory.

My glow plugs, high idle, and cold advance are all manually controlled.

James