Resistor Wire

[gooch66]

The brown resistor wire gets really hot, almost too hot to touch. Should it be that hot? If it is, what is the best insulator to use or should I insulate? If not, what could be the cause? I am worrying about it frying the other wires.

 

[DaveLev]

what year, what type of wiring (factory, american autowire, etc.)?

 

[Viperwolf1]

The brown resistor wire gets really hot, almost too hot to touch. Should it be that hot? If it is, what is the best insulator to use or should I insulate? If not, what could be the cause? I am worrying about it frying the other wires.

Yes it does. Don't leave the key on long without the engine running.

 

[DirtDonk]

Unless it was left off of yours for some reason, there should have been a heat-resistant sleeve around it under the dash. If this is the wire you're talking about?
If the Brown wire between the starter relay and the connector near the firewall, that's not a resistor wire and should not get hot.

Presumably though, you're talking about the one under the dash. It does get hot, it should have a protective sleeve around it, and like Viper said, don't leave the key in the RUN position for any longer than you have to.

Paul

 

[DirtDonk]

Good questions and your 200th post too Dave!
Congrats!

Paul

 

[gooch66]

what year, what type of wiring (factory, american autowire, etc.)?

It's a '75 with original wiring as far as I can tell. I have been going through it with the wiring diagrams from seabiscuit the get the rats nest of wires straightened out. Takes a lot of time.

 

[bobo8929]

I'm looking to solve a "burning smell" that pops up when I'm going 50+ MPH and thought I'd take a look at the resistance wire. I have a '66 that's a Aug '65 production so it's very early. Everything is stock (ignition, coil, dist)

I'm going to replace the resistance wire (16 - pink) and noticed the protective sleeve only runs 1-2 feet. The rest of the resistance wire was wrapped up with all the other wires running back to the harness at the firewall. I thought this was weird.

So I'm going to replace the wire but wasn't sure where I should make the cut on the old wire. It runs directly into the harness so I don't know if I can take it out and run the new one (bullet male) into the harness.

Anyone have any thoughts?

 

[DirtDonk]

I think we can "assume" (hate to, but seems reasonable at this point) that the resistor portion that gets hot is only the portion you can see that's separate from the rest of the harness.
If it gets hot enough to protect the other wires from it, then they would not have wrapped it in the same loom. I have a harness here to dissect, but haven't had the time. But if you just cut the exposed portion that has it's own heat wrap, that's likely the resistor section and all the rest is regular wire.

But have you measured the resistance? I would do that first. If it's higher than spec, then that's likely your smell as it's getting too hot and starting to overheat the jacket. But if it's within spec, you might keep looking further for some other culprit.
Certainly don't want to ignore a potential fire hazard under your nose!

Paul

 

[Steve83]

I'm looking to solve a "burning smell"...and thought I'd take a look at the resistance wire.

Looking probably isn't the best method to find a smell. Did you SMELL the resistor wire? Did you smell it immediately after you noticed the smell in the truck?

Everything is stock (ignition, coil, dist)

Are you saying there's not one electrical modification to the truck? No replacement bulbs; no aftermarket radio; no trailer plug; no off-road lights; no winch; no alarm...?

I'm going to replace the resistance wire...

Why? With what? Did you do some test that you didn't mention which identified a fault in the resistor wire? If not; why would you think a replacement resistor wire would work differently (assuming you can get one)?

I thought this was weird.

Why? have you seen many resistor wires set up differently from that one?

...the new one (bullet male)...

What does that mean?

Anyone have any thoughts?

All the time. ;D

But have you measured the resistance? ... If it's higher than spec, then that's likely your smell as it's getting too hot

If the resistance is higher, then less current would flow, and it would be cooler.

High resistance in a normal circuit causes heat because the wire isn't sized to handle heat - it's sized only to conduct electricity. If unwanted resistance converts some of the electricity to heat where it shouldn't, that spot gets hot.

But the resistor wire is designed to dissipate the heat, so it behaves differently.

Certainly don't want to ignore a potential fire hazard under your nose!

...or misdiagnose it, and tear into something that's working right.

 

[DirtDonk]

Pretty sure his reference to the bullet connector is on the resistor wire near the ignition switch.
Some years used an easily replaceable resistance wire "module" if you will. I actually went down and bought one once. Still have it in the box in the garage. Can't remember at the moment if it was from Ford or just down at the auto parts store.

Remember when we were talking about the ignition switch wiring and fuse panel labeling a few months ago? I know the discussion was about the panels, but also about what color the resistor wire was at the switch connector.
Some were the Pink color right up into the switch, while others were one of the Red w/green or Green w/red colors and then changed to Pink after the bullet connector.

Paul

 

[DirtDonk]

The Green bullet type connector is where the resistor wire starts on this '73 harness.
Others I've seen have just the single wire run all the way into the black connector without any kind of plug.

Paul

 

[Steve83]

Pretty sure his reference to the bullet connector...

Ah, OK - thanks.

 

[jdbronco]

I'm looking to solve a "burning smell" that pops up when I'm going 50+ MPH and thought I'd take a look at the resistance wire. I have a '66 that's a Aug '65 production so it's very early. Everything is stock (ignition, coil, dist)

I'm going to replace the resistance wire (16 - pink) and noticed the protective sleeve only runs 1-2 feet. The rest of the resistance wire was wrapped up with all the other wires running back to the harness at the firewall. I thought this was weird.

So I'm going to replace the wire but wasn't sure where I should make the cut on the old wire. It runs directly into the harness so I don't know if I can take it out and run the new one (bullet male) into the harness.

Anyone have any thoughts?

When I re-wired mine I removed the resistance wire and added a straight 12V wire with a ceramic ballast resistor on the firewall near the brake booster. Didn't try very hard to find the whole wire but knew you could get the resistor for cheap so I went that route. They do get really warm so put them by themselves.