861 alternator wire glowing red

Blueox4 · Jan 23, 2021

On my 861 when I start the tractor the red wire with the electrical tape to my alternator glows fire red and will actually burn the tape. Once the tractor start it stops
glowing or burning. Do I need a new alternator or do I have excessive voltage going to the alternator? The tractor has been converted to 12v years ago and this just
seemed to start. New alternator or other issue?

pomester · Jan 23, 2021

So, it glows when the start switch is pushed down and stops when the switch is released?

The glow means the wire is shorted to ground. If it's only shorted to ground when the switch is depressed, that suggests an issue at the solenoid. Located behind the air cleaner, it should have two big terminals and two small terminals. The alternator red wire should hook to the same terminal as the cable coming from the battery. The start button hooks to the small terminal next to it. See if a poor install has allowed the alternator wire to short against the starter switch wire/terminal.

When you get it figured out, you need to take the terminal loose at the alternator, clean up the post, and install a new end on the red wire.

Blueox4 · Jan 23, 2021

Thank you very much for putting me on the right track! What had happened is I put in a pretty large battery that hung off the battery tray a bit on that end so I bungied it
to the battery tray support. What it apparently did was push up against the wiring you mentioned causing a short. When I removed the bungie cord and stuck my hand
back there and fluffed out the wires that were crushed by the battery all was good! No glow there when I started. Thank you very much for the help and best to you!

warbaby · Jan 23, 2021

Get someone over there that understands your Ford's charging system! You could have an internal short-to-ground inside the alternator, a bad insulator where this terminal passes through the body of the alternator, maybe your red wire's over-sized terminal could be touching the side of the alternator causing a ground, you could have a bad or incorrectly wired regulator, some damaged or badly routed wiring or maybe even a reversed polarity of your charging system (battery hooked up "backwards")??

You'll probably need a few new charging system parts right now, or if you let it continue, a new tractor after the inevitable electrical fire. Figure in the cost of a new garage/house or barn if you also like to park it inside...

Bern · Jan 23, 2021

You have high resistance at the attaching nut, which causes excessive voltage drop, which creates heat. Clean it up and your problem will go away.

861 alternator wire glowing red

Blueox4

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pomester

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Blueox4

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warbaby

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Bern

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