In my 79 F250 instrument cluster there is a wire from plug 14 that seems really thin or brittle...it gets really hot....I'm wondering what it goes to? There are 2 black wires out of plug 14. ...one is suppost to be a ground, the other is wire 48...I have no clue....

It is physically hot when I touch it when truck is running. I was thinking of replacing it with a thicker wire.....

Any help would be appriciated.

 

uhm, I looked at the wiring schematics, and have no idear what plug 14 and wire 48 is...

Got any pictures to help point the way

The Ammeter wires at R-0 (Red Orange?) and Yellow-Black... If so, did you or PO upgrade the Alternator Amperage perhaps causing a lot more current to flow through the wires?

*shrugs*

Hot wires are something to worry about though, I burnt up my ignition coil resistor wire and that was scary enough.

 

This is the plug that goes into the back of the instrument cluster... Pin Number 14 is on right side in this pic and has 2 wires 48 and 30 which is a ground.

 

Ah okay, I found a schematic for this: http://fordification.net/tech/images...aster_3of9.jpg
And the rest: 1973-1979 Ford Truck Wiring Diagrams & Schematics - FORDification.net

Wire 48 is terminated in the wire harness? Weird...
Wire 30 comes from a resistor or resistor wire... perhaps the IVR (Instrument Cluster Voltage Regulator) is acting up?

 

Yeah, I had noticed that on the diagram too. When I recently rebundled my harness, I noticed it. It just goes about six inches, connects to nothing, and is hidden in the harness. No clue why they did that.

 

How are the gauges?

This wire supplies voltage to the IVR (through a resistor or resistor wire from Ignition switch), and the IVR supplies voltage (5-ish volts?) to the gauges.

 

My gauges did work after I got my truck back from the transmission shop...but I never noticed the wire was hot before I took it in. I'm running a 7.3 idi diesel

This wire seems frail it is is very soft or spongy....not sure how to describe it.

 

My gauges did not work after I got my truck back from the transmission shop...but I never noticed the wire was hot before I took it in. I'm running a 7.3 idi diesel

This wire seems frail it is is very soft or spongy....not sure how to describe it.

 

I just plugged in another instrument cluster from my other 79. Gauges don't work on it either....turn signals, bright light indicator works on both clusters...no lights or movement from any gauges on either cluster. I know my gauges have worked.

Lighted heater and steering column light works

 

What does the Instrument Cluster Voltage Regulator look like?

 

Ok I think I found the Instrument Cluster Voltage Regulator. Would it be bad?

 

Seems to be bad...

I'm guessing the wire is soft and spongy because it might be a resistor wire. Like the Ignition Coil Resistor wire is different than regular wire.

I'm just worried that the wire is damaged or something... Think I'm going to go out and check if mine over heats any...

I did an Image Search for Ford IVR and found this:
https://www.ford-trucks.com/forums/1...ing-gages.html
Guy replaced the innards with a 7805 voltage regulator. Not sure you want to go this route, but interesting to see.

How to Diags an IVR: https://www.ford-trucks.com/forums/1...t-the-ivr.html

YouToob Video, although it's an '88 T-Bird, the IVR is the same: