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JD 4440 alternator wiring ?
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JDAmericanFarmer
Posted 2/3/2017 11:51 (#5814106)
Subject: JD 4440 alternator wiring ?


Central MN
Am I correct that the number 1 terminal should only got when the key is on? And #2 terminal is always hot? Must have a bad or broken wire because have no juice at at all. But I think I found the same wire up by the firewall as it has power with only the key on and it looks like a regular wire but it only has one little tiny actual wire in it. And could I cut it and splice a new wire down to the alternator or will there be an issue since that wire is just one little tine wire inside?



(IMG_20170129_133940977.jpg)



(IMG_20170129_134002827.jpg)



(IMG_20170129_134017496.jpg)



(IMG_20170129_134033256.jpg)



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Attachments IMG_20170129_133940977.jpg (234KB - 275 downloads)
Attachments IMG_20170129_134002827.jpg (166KB - 201 downloads)
Attachments IMG_20170129_134017496.jpg (212KB - 189 downloads)
Attachments IMG_20170129_134033256.jpg (201KB - 192 downloads)
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Buster 50
Posted 2/3/2017 12:06 (#5814143 - in reply to #5814106)
Subject: RE: JD 4440 alternator wiring ?



North West IA/western AZ
The small wire is a resistance wire IIRC. Not sure if you can replace with regular wire or not. I bought a new one from Deere many years ago.
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Rasor Farms
Posted 2/3/2017 12:55 (#5814264 - in reply to #5814106)
Subject: RE: JD 4440 alternator wiring ?



southeastern ohio

Yes, that how ours is wired

Tim

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Jon Hagen
Posted 2/3/2017 13:30 (#5814326 - in reply to #5814106)
Subject: RE: JD 4440 alternator wiring ? (PIC)



Hagen Brothers farms,Goodrich ND
JDAmericanFarmer - 2/3/2017 11:51

Am I correct that the number 1 terminal should only got when the key is on? And #2 terminal is always hot? Must have a bad or broken wire because have no juice at at all. But I think I found the same wire up by the firewall as it has power with only the key on and it looks like a regular wire but it only has one little tiny actual wire in it. And could I cut it and splice a new wire down to the alternator or will there be an issue since that wire is just one little tine wire inside?




That single strand resistor wire is a common failure on 30-40-50 series JD's. The resistor wire kit from JD is a bit expensive IMO , seems I remember about $50. What worked on my 4450 was to salvage a two wire side marker light from a 70's Ford car, wire one wire of it into the firewall connection where the resistor wire goes,, zip tie the light to the engine breather tube, and use standard non resistor wire from light to alternator #1 terminal. The light serves as the necessary resistor, and gives you a visual indicator that the alternator field circuit is working. My cost was less than $2.

One thing I see in your picture that always scares the jeebers out of me is bare terminals plugged into the alternator. That #2 sense wire is only 1/8 inch from touching the alternator case and is direct to the battery with no fuse. If something tugs on that unfused wire and shorts it to the alt case, your harness/ tractor/ tractor shed will burn up, as that wire will be red hot in seconds. To make it safe, a Delco alternator harness repair plug is only $3 at your local auto parts store. It makes it a safe and professional looking repair.

Edited by Jon Hagen 2/3/2017 14:25




(Alt plug kit.jpg)



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Attachments Alt plug kit.jpg (80KB - 161 downloads)
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ccjersey
Posted 2/3/2017 16:00 (#5814527 - in reply to #5814326)
Subject: RE: JD 4440 alternator wiring ? (PIC)


Faunsdale, AL
I would open the harness up a little if necessary to find where the resistor wire is broken. Most likely it is in the exposed wires at the alternator end since that is where it can flex. pull on the terminal/end of the wire and see where the insulation stretches or if the wire pulls out you can lay it along the insulation to see where break was.

If no luck with that, Jon's fix with the bulb works just fine too.

I found one broken just next to the firewall where you show it opened up. Was able to crimp a splice in it and fix it.
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mac4440
Posted 2/3/2017 19:23 (#5814898 - in reply to #5814326)
Subject: RE: JD 4440 alternator wiring ? (PIC)



What's the reason for using a resistor?
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ccjersey
Posted 2/3/2017 20:25 (#5815035 - in reply to #5814898)
Subject: RE: JD 4440 alternator wiring ? (PIC)


Faunsdale, AL
I think it is easier on the regulator, but I have used plain wire on several and they lasted as well as any others.
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JDAmericanFarmer
Posted 2/3/2017 20:45 (#5815086 - in reply to #5815035)
Subject: RE: JD 4440 alternator wiring ? (PIC)


Central MN
OK thanks guys. I check that out Jon thanks. Yep I will get one of them plugs that belongs on the alternator, my old one got wrecked front taking it on and off and used these as temporary for testing. Yes I was hoping to find the bad spot and just splice it, is there better but connectors work good for tine single string wire? Thanks guys.
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jlv03
Posted 2/3/2017 21:18 (#5815166 - in reply to #5814898)
Subject: RE: JD 4440 alternator wiring ? (PIC)


I think it's there to prevent back feeding when you shut the ignition switch off.

We had a 4430 once that would keep the radio on with the key on off, until the fuel stop was pulled.
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Jon Hagen
Posted 2/3/2017 21:20 (#5815173 - in reply to #5814898)
Subject: RE: JD 4440 alternator wiring ? (PIC)



Hagen Brothers farms,Goodrich ND
mac4440 - 2/3/2017 19:23

What's the reason for using a resistor?





Without the resistor, the charging alternator can back feed through the #1 regulator terminal into the ignition circuit and prevent shutting down a gas engine ignition system or a diesel pump with electric shut down. The resistor limits backflow to a level too low to run these systems.
Also, without the resistor, an open output wire between the alternator and battery will allow the alternator to try to push it's full output through the #1 regulator terminal, to the battery, which will fry the alternators regulator and diode trio.

As CC says though, wire direct from switched battery power to the #1 terminal will often work without problems, just a little more chance of run on or alternator damage if something goes wrong in the wiring.
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