Truck died on me while driving, luckily as i was coming to a stop already...
truck would not start and right away i saw and smelt some smoke coming from somewhere.
Upon popping the hood i could see some melted tape on the main wiring loom.
Truck wouldnt start and didnt think it was gonna be an easy fix so got er towed home
Anyone know what these 2 blue wires are and what may have caused it? They melted together.
I freed the wires of each other and the truck started and ran .... little worried its just gonna happen again

Thanks!

 

Looks familiar. What year is your truck and can you see any colored strips on the wires?

 

93.
Dont think so, they both look solid blue

 

How are your electrical and troubleshooting skills? Do you have access to the wiring diagrams? Guessing from the wiring diagrams one or both of those wires can be main power feeds off the ignition switch and/or auto shutdown relay. You need to isolate the wires and find where they come from and what they go to. That would be of great help identifying all the circuits they can affect. The worst part to electrical on these old trucks is previous owners hacking up the wires to install some toy or attempt to fix a problem without knowing what they are hacking into. My own 92 is a case in point.

 

Not great with electrical, but planning to dive deeper this weekend...ill try and get more pictures
Thanks for the messages

 

A bit further along the suspect wires join a 3rd blue wire for a moment then go back to separate....

 

Here is where the wire goes into the bulkhead. According to this diagram its #47 which is Ignition Run & Start...

Any input appreciated

 

Something that runs only when the key is on. Heater blower, Radio, Wipers...etc...

 

IRCC, The dark blue wire is the main ignition switch powered wire going to the IP shutoff solenoid (why it won't run), but also other places, one of which is the transmission. Anyway, as I recall, it goes all over, is poorly protected, probably only by a fusable link, and is subject to abuse from rubbing on throttle linkage, the frame, etc.

At this point, you need the 8W wiring diagram section of the service manual, available here, a voltmeter, patience, and basic electrical knowledge. Track it down to the original short and repair the damage done.

 

Thanks Gents, I believe I located the faulty wire, it was almost fully broken near the ASD relay...
Seems like that relay is also linked into this run of wires.

 

Alright, I'm almost ready to piece it all back together.

The only weird thing left is this connection, there's 2 of them in this run. Where 4 wires are fused and turn into 2, and 3 wires are fused back to 3 wires...

Should I just strip the new wire and wrap it to this fusion? Might be able to cut the wire, leave a enough to strip it and just connect the new one that way.
Could also get those butt connectors with different sizes on either side and fully re-do this connection?

Thanks for the advice


connection beside the duckfoot

 

You should use the Butt connectors rather than just wrapping a new wire around the joint.

 

The famous "Jim Lane" sold me on these over a decade ago. I do not use anything but these and have a shrink tube over them. They do NOT Fail. You can even dabble a bit of dielectric grease in each end if you're ever thinking they'll get wet, bypassin the shrink wrap.

Bare wire BUTT Connectors (crimp style)

 

Are those any different than your standard insulated butt connector? ( minus the insulation) ?
I read Jim Land talk about some special butt connectors used by HVAC installers.....

 

Figured I'd post a couple pics of the bulkhead connector and what I had to do to remove the faulty wire with the male connector in case someone runs into this


little blue plastic tab under gasket
.

There's a rubber gasket on the inside, you have to peel it back, hard to do without destroying it, Then there's this blue piece of plastic you have to pry out of there, then there's a little tab that will release the wire and connector.

These connectors are hard to find, there was a place in Texas that had em but wont ship to Canada.....I managed to salvage mine and open the crimp and solder the new wire in....

Back on the Road!