Wire gets warm when ignition is on

[Rangerbj]

A pinkish wire coming from my ignition switch and runs thru the firewall into engine compartment, and then who knows where, is getting warm when ignition key is turned to ON either when engine is running or not running. The wire appears to be original to the wire loom as it was wrapped with other wires. Also it has an extra wrap on it when bundled with other wires.

I have a 1969 bronco with a 302 that did not come with the bronco. It also has the electronic ignition box as the 1975 model bronco came with standard.

So, what is wrong and how can if fix it?

Thanks

 

[SP73]

That is most likely a resistor wire. Resistance in an electrical circuit will produce heat, so it may be normal. How warm is it?

 

[DirtDonk]

As said, nothing wrong. Just normal condition.
Well nothing wrong except that you're leaving the key ON while the engine is not running that is! Never do that.

It's a good habit to get out of. In fact it's one of the first things we used to learn in the old days of points ignitions, but it still held true for many years with pre-computer electronic ignitions.
The components can overheat and fail. Usually it takes more than a couple of minutes. But not always, so why take the chance?

As SP said, that's your resistor wire. In the electrical world, resistance = heat and heat = resistance. So the ignition coil wire, in order to reduce voltage to a working level of about 8 or 9 volts instead of 12 to 14 volts, is smaller in gauge, extra long (hence the multiple loops), special high temperature rated conductor and outer covers, as well as a high-temp insulating wrap to keep the heat inside and the other wires safe under the dash.
Makes it hard to cut and splice it (which it has a warning against printed on it's outer jacket), but you usually don't have to mess with it.

Paul

 

[SP73]

As said, nothing wrong. Just normal condition.
Well nothing wrong except that you're leaving the key ON while the engine is not running that is! Never do that.

It's a good habit to get out of. In fact it's one of the first things we used to learn in the old days of points ignitions, but it still held true for many years with pre-computer electronic ignitions.
The components can overheat and fail. Usually it takes more than a couple of minutes. But not always, so why take the chance?
Paul

I was thinking along the same lines, but neglected to add it, so thanks! We sure appreciate you brother!

 

[Rangerbj]

Also, the wire does NOT to go the fuse box. Just straight through the firewall with other wires in an original rubber grommet.

 

[Rangerbj]

Thanks guys. You gave me important information especially about leaving key ON!!!

Also, that wire was very long as you pointed out earlier.

I love this site. So many good experts.

Thanks much to all

 

[DirtDonk]

Also, the wire does NOT to go the fuse box. Just straight through the firewall with other wires in an original rubber grommet.

Something else unique about that particular wire. It shares a contact point on the ignition switch with the Green w/red wire that turns on the voltage regulator under the hood and both go straight to their respective components without routing through the fuse panel or other things first.
That is the only contact on the ignition switch that is hot in ON only. And this is how you can run your radio all day long and not bugger the ignition components or drain the battery extra quickly.
So it's just the ON position that you need to be mindful of.

Accessories that are wired to the center post of the ignition switch via the Black w/green wire are hot with the key in both ACC and ON positions, and many of those are fed through the fuse panel. But not all...

Later model Broncos, and other model vehicles had some additional circuits, but up to a point on Broncos those were the only three regular ACC/ON power feed wires from the ignition switch.

Paul