2640 Charging Proublems

[jdman2009]

I’ve read and read about others with the same problems but haven’t seen really anything about the fixes. I’ve got a 2640 with Motorola alternator that has separate regulator. I’ve had alternator checked
( everything good) and put a new regulator. It won’t charge any but I don’t have power on the alternator wire that excites it. I have switched power going into the regulator but no power coming out. Does the wire that supposed to excite the alternator get its power from the regulator or where? If so does that mean the new regulator is bad? I have nothing coming out of it.
Thanks if anyone knows and no I don’t want to change it to a one wire alternator which I know someone will recommend.

 

[Jim.ME]

Sounds like a bad regulator. Have you checked and cleaned all the connections in the charge circuit? Do you have the 2440/2640 technical manual TM1142? It has a good bit of info for checking the charging circuit components right on the tractor. The wiring diagram shows power to the alternator field comes from the regulator.

 

[jdman2009]

Yeah I’ve got the manual. Wouldn’t expect a new one to be bad but guess never know. I can’t really check like the book says because I don’t have power on that wire. Any chance the plug wire orientation could be wrong on the ne regulator? The colors don’t really match and some are a different color.

 

[Jim.ME]

Yeah I’ve got the manual. Wouldn’t expect a new one to be bad but guess never know. I can’t really check like the book says because I don’t have power on that wire. Any chance the plug wire orientation could be wrong on the ne regulator? The colors don’t really match and some are a different color.

So you have to work back from the alternator to the regulator to see if there is a broken wire. Check that the connector at the regulator plugged together correctly. Use the manual to figure out the wires from the regulator. Unplug the connector near the regulator. Use a jumper wire to put power into the regulator at the connector close to it and see which wires, if any have power coming out of the regulator.

It is not safe to just count on wire colors being correct. It is possible the regulator is bad, process of elimination should tell. Did you get the regulator where you had the alternator tested? Can they hook them up and try running them together?

 

[Harry in Ky]

Does the battery charge indicator light work? If not the system will probably never be excited. I've found a number of those old spring loaded bulb holders to be problematic. They often require some careful cleaning and sometimes a new bulb.

 

[jdman2009]

So you have to work back from the alternator to the regulator to see if there is a broken wire. Check that the connector at the regulator plugged together correctly. Use the manual to figure out the wires from the regulator. Unplug the connector near the regulator. Use a jumper wire to put power into the regulator at the connector close to it and see which wires, if any have power coming out of the regulator.

It is not safe to just count on wire colors being correct. It is possible the regulator is bad, process of elimination should tell. Did you get the regulator where you had the alternator tested? Can they hook them up and try running them together?

No I ordered it from all states ag. No they don’t have anyway to check the regulator and the charge indicator light does work

 

[Jim.ME]

No I ordered it from all states ag. No they don’t have anyway to check the regulator and the charge indicator light does work

Did they spin your alternator on their machine to check it? Some of those machines they can use jumper wires to hook up the regulator to the alternator and duplicate running on the tractor.

If you use a jumper wire to put power to the alternator field terminal when running does the battery voltage go up? The manual shows a "field resistor" to limit current to the field, but you can jumper it without a resistor for a moment and check for voltage rise. The manual gives you that procedure.

I am guessing you got regulator # 125218 from PartsASAP, they show it as a replacement on many models. The wire colors may be right for some of the tractors the aftermarket regulator fits. The connection location in the plug connector should be in the correct location, regardless of wire color. As I posted (#4) see if there is power coming out of the regulator on a connector that matches to the wire that goes to the alternator field.

 

[jdman2009]

There isn’t any power coming out of the regulator. I have it on both sides of the plug going in but nothing out. If I take a hot wire to the field it will kick in and charge. It’s not the alternator and all wires omed out just didn’t expect a new regulator to be bad. The 125218 regulator is what I got.

 

[Jim.ME]

There isn’t any power coming out of the regulator. I have it on both sides of the plug going in but nothing out. If I take a hot wire to the field it will kick in and charge. It’s not the alternator and all wires omed out just didn’t expect a new regulator to be bad. The 125218 regulator is what I got.

It certainly points towards a bad regulator.

 

[jdman2009]

It certainly points towards a bad regulator.

I got another regulator and same thing I still don’t have any power coming out of it. Got it going in and to the regulator then nothing! I can feel the regulator getting warm in just a minute or two. I took a jumper on the alternator and it will start charging. What’s the chance of getting 2 bad regulators? If that’s still the problem only thing left is to get it from JD!

 

[Jim.ME]

I got another regulator and same thing I still don’t have any power coming out of it. Got it going in and to the regulator then nothing! I can feel the regulator getting warm in just a minute or two. I took a jumper on the alternator and it will start charging. What’s the chance of getting 2 bad regulators? If that’s still the problem only thing left is to get it from JD!

According to the wiring diagram the indicator light wire attaches into the excitation wire (the wire to the field terminal) going to the alternator on the alternator side of the regulator connector. That would indicate that with the key in the run position there would be power to the alternator excitation circuit without the regulator. Have you checked that? Does the indicator light work? Look at section 40 page 10-2 (figure 1) for the charging circuit.

 

[jdman2009]

This is what mine shows. My altinator is arranged differently and doesn’t have any markings.

 

[Jim.ME]

This is what mine shows. My altinator is arranged differently and doesn’t have any markings.View attachment 130279View attachment 130280

Part of the problem here is that is a manual for a 2240. By the parts book the 2240 uses a Bosch charging system. Your 2640 has a Motorola system. The wiring diagram is different for a 2640.

 

[jdman2009]

This is what mine shows. My altinator is arranged differently and doesn’t have any markings.View attachment 130279View attachment 130280

Looking at what the regulator says the red wire on the regulator goes to the isolation diode. Does that mean it should go up at the top where the bigger wires are or on one of those post beside it instead of the bottom left like it is? I bought it like this they had replaced the alternator JD reman and may have hooked it up wrong?

 

[jdman2009]

Part of the problem here is that is a manual for a 2240. By the parts book the 2240 uses a Bosch charging system. Your 2640 has a Motorola system. The wiring diagram is different for a 2640.

View attachment 130281

I realize that but manual is for both and that is the only one it has in it. It’s a I&T

 

[Jim.ME]

I would say they hooked it up wrong

I realize that but manual is for both and that is the only one it has in it. It’s a I&T

It is wrong as far as I am concerned, it does not match the 2440 and 2640 John Deere technical manual drawings. The JD manual has about 20 pages of different wiring drawings. As I said your 2640 is a Motorola system and the 2240 is a Bosch system. They are different manufacturers of alternators and regulators. The part numbers for both brands are different by OEM and aftermarket. I asked you way back if you had the "2440/2640 technical manual TM1142" and you replied you had the manual. The I&T is not that manual; no wonder you weren't seeing the troubleshooting info I was referring you to. I am guessing the regulator "isolation diode" that instruction sheet is referring to is the plate on your alternator with the battery output and other two terminals in it (which is called the isolation diode assembly in the alternator breakdown in TM1142).

Red is not a color related to the regulator wires in the JD technical manual. I am guessing it is the orange wire on the JD manual that comes from the indicator light to the regulator. There is a second orange wire from the same side of the indicator light that goes to the terminal just to the right of the alternator output terminal in the Isolation diode assembly. Turning the key to on/run sends power to the indicator light the wires to the regulator and alternator from the indicator light give them power to excite the alternator.

As I asked before does the indicator light work? If it does it appears you should have power at the terminal of the alternator when you unhook the wire I marked as orange in your drawing

Edited to add missing words.

 

[jdman2009]

That was the problem moved the orange wire to that location and it worked fine. The indicator light always worked it just wouldn’t kick in to charge. All is good now 14.5 volts

Thanks For the info!

 

[Jim.ME]

Glad to hear you got it.

Please get a John Deere TM1142 manual for your tractor. There is a new Jensales reproduction one on eBay right now for less than $60. That is the same one I have and is a clear, clean reproduction, some are not. I would be skeptical of trusting the electrical info in the I&T manual you have given they lumped the electrical info for two different electrical systems by different manufacturers. The right manual and a picture could have saved some time.