12 v system charging system

[JamesWalker]

I have put a new alternator on my to20, checked the wiring per diagram. Ammeter never records any thing, the battery reads 12.9 volts not running, tractor starts fine, but the voltmeter goes to 0 while tractor is running with leads attached in the same place. The whole system was replaced before I got it, and a keyed switch was used. The only wiring diagram I can find does not have a key switch. Really need some help.

 

[used red MN]

Okay, I am not as familiar with the Ferguson wiring lay out
as I am with Farmalls but I am sure I can help you out.
First I need info about the alternator one wire or 3
wire? Is it a Delco 10si or other? Did you buy it new if
so where? You wired it per a diagram can you show me
the diagram by a link or photo. If it is a link, if you do
not know how to post a link tell me if post in Modern or
Classic and I will explain how. Tell me if the key switch
is off-on-start or only ignition off-on. Look at the
..generic.. diagram I am attaching. The two
connections off the ammeter shown as heavier lines
should be 10 gauge wires. The one on the left
connection should go to the end of the positive battery
cable opposite end from the battery wherever that
connects. The one on the right should go to the
alternator stud terminal. The battery voltage should be
tested at the battery posts, if I ask what is the voltage
when you do xyz that is what I mean, voltage at the
battery terminals. If I want a voltage check somewhere
else I will instruct you where to test. I assume by volt
meter you are referring to a test meter if you are
adding a volt meter to the tractor let me know about
that.
Edit to add: Where I reference the linked diagram above I am suggesting to compare your wiring to this. I believe diagrams supplied with some one wire alternators do not show connections through the ammeter. In my opinion this setup would require using a volt meter gauge instead of the ammeter. If you are considering this beware a volt meter wires in very different from an ammeter.
Generic 6 to 12 volt conversion diagram adding alt.


This post was edited by used red MN on 11/20/2023 at 06:36 am.

 

[560Dennis]

Zero charge at idle Possible small pulley on tractor (driver). When engine revs up over the alternator 1200 charges.
Does alternator have an internal voltage regulator ,or is it an external mounting of voltage regulator ?

 

[ken44520978]

If you are using a digital volt meter you may be getting false readings when the tractor is running. If
you have access to an analog voltmeter give it a try to verify interference isn't confusing the digital
meter. I have seen it happen many times.

 

[Hemmjo]

When you say with the leads attached in the same place, where exactly are the leads connected?

It is very possible for you to get the results you mention depending on where the leads are connected.

 

[Jim.ME]

You need to provide more info, no one here can see your tractor. The parts book shows a keyed ignition switch for the TO20. Do you mean the switch was changed to one with a start position and a solenoid added so that the starter is engaged by the key switch, not the gear shift lever as original?

As has been asked, what alternator? Internal or external regulator? Is the pulley width correct for the original belt width? What is the diameter of the pulley?

What wiring diagram did you use?

Can you make and post a sketch of the wiring as you have it currently connected?

It sounds like your tractor has an ammeter and you are using a handheld voltmeter for testing. What wires are connected to which terminal of the ammeter? Where are you attaching the leads for your test meter to the tractor?

 

[used red MN]

Ya Jim no response. I can only believe that the diagram
I posted gave him what he needed. I know rustred has
mentioned that some new one wire alternators show
the main output terminal wiring going directly to the
positive battery cable connection. Which would
obviously eliminate any reading by an ammeter.

 

[Jim.ME]

The new ones that wire the alternator directly to the battery source likely use a voltmeter or trigger a warning or a check engine light if the alternator is not charging.

 

[used red MN]

Well I am sure you know rustred he said, I do not need
a gauge or light telling me the alternator is working
every second. I can see his point to a degree,
alternators are fairly reliable.

 

[Badbrad59]

Okay, I am not as familiar with the Ferguson wiring lay out
as I am with Farmalls but I am sure I can help you out.
First I need info about the alternator one wire or 3
wire? Is it a Delco 10si or other? Did you buy it new if
so where? You wired it per a diagram can you show me
the diagram by a link or photo. If it is a link, if you do
not know how to post a link tell me if post in Modern or
Classic and I will explain how. Tell me if the key switch
is off-on-start or only ignition off-on. Look at the
..generic.. diagram I am attaching. The two
connections off the ammeter shown as heavier lines
should be 10 gauge wires. The one on the left
connection should go to the end of the positive battery
cable opposite end from the battery wherever that
connects. The one on the right should go to the
alternator stud terminal. The battery voltage should be
tested at the battery posts, if I ask what is the voltage
when you do xyz that is what I mean, voltage at the
battery terminals. If I want a voltage check somewhere
else I will instruct you where to test. I assume by volt
meter you are referring to a test meter if you are
adding a volt meter to the tractor let me know about
that.
Edit to add: Where I reference the linked diagram above I am suggesting to compare your wiring to this. I believe diagrams supplied with some one wire alternators do not show connections through the ammeter. In my opinion this setup would require using a volt meter gauge instead of the ammeter. If you are considering this beware a volt meter wires in very different from an ammeter.
Generic 6 to 12 volt conversion diagram adding alt.


This post was edited by used red MN on 11/20/2023 at 06:36 am.

Hey used red MN do you have a diagram for a diesel tractor charging system? I’m trying to get my JD 2240 to where the alternator actually charges the battery while it’s running!
Thanks

 

[Badbrad59]

Here is the alternator I have.

 

[Badbrad59]

Also I’m starting from scratch cause the wiring harness was in terrible shape! No gauges or anything!

 

[Jim.ME]

Here is the alternator I have.

Welcome to the forums. It is generally best to start a new thread of your own rather than tag on the end of someone else's, especially if it is not active. Often people read the first post of a thread, missing the original date, and reply to it rather than your late arrival.

I doubt used red has what you want and I doubt you will find it free on the web. If you are lucky someone here might have a copy and can help you, but your tractor serial number is needed to get the right manual.

You need the wiring diagrams from the technical manual. The John Deere Bookstore shows TM 4301 (about $88.00) for tractor serial numbers 349999 and before. TM 1221 (about $150.00) covers both the 2240 and the 2040 starting with serial number 350000 and those after that.

The YT store has a reprint of the TM1221 for about $90.00 plus shipping. The do not have the TM4301. They have an I&T manual (JD 202) for about $30.00 plus shipping, that says it has wiring diagrams for the 2240 along with several other models, how complete those diagrams are compared to the JD ones I cannot say.

All of these can be found as used OEM, reprints, and electronic copies on eBay and other places at varying prices. Use the JD manual number for your tractor serial number in your search not just 2240. Be aware that some reprints are incomplete, or of poor quality, and some electronic copies are incomplete, poor quality and a jumbled mess. I would look for a good used copy of the OEM manual for the serial number range of my tractor, if I was in your position.

Here is a link to the JD Bookstore if you want to check. Click on Equipment Publications to get to the search page. The Operator's Manuals are free to download and save. Hard or electronic copies of those are purchase items are as all the other manuals.

JD Ag & Turf Bookstore

Edited to add welcome.

 

[Badbrad59]

Thanks for the reply Jim! And the advice! I’m trying to wire the alternator without the tractor wiring harness! Basically building my own harness just for the charging system! It appears I’m not exciting the alternator? I installed a 12 volt indicator light from the ignition switch to the D+ connector hoping to excite it but the voltage never changes when alternator is spinning!

 

[used red MN]

Thanks for the reply Jim! And the advice! I’m trying to wire the alternator without the tractor wiring harness! Basically building my own harness just for the charging system! It appears I’m not exciting the alternator? I installed a 12 volt indicator light from the ignition switch to the D+ connector hoping to excite it but the voltage never changes when alternator is spinning!

Brad welcome to YT! By a web search it looks like the terminal D+M5 should go to the light. The large terminal by at least a 10 ga wire to battery positive (+) at the starter. I know minimal about the internal layout of that Bosch alternator, the above is a best guess based on net info. Is there only one terminal in the plug area labeled W6.3? I find the one “flat” is for an electronic tach signal in some applications.

 

[Badbrad59]

Yes only one plug! I’ve decided to send the alternator back since it wasn’t an exact match to the old alternator! Here’s a picture of the old one!

 

[Jim.ME]

Yes only one plug! I’ve decided to send the alternator back since it wasn’t an exact match to the old alternator! Here’s a picture of the old one!

Personally, if I was going to rewire it all, I would go to the parts store and get a Delco type 10SI 3 wire alternator which will work with the indicator light and forget the Bosch alternator, which is what I think you have. If you have trouble with the alternator in the future, the Delcos are readily available and relatively in expensive. I would put a voltmeter in place of the indicator light, if I used a Delco type one wire, as not all of those will work an indicator light. The other thing is to be sure you have a small diameter pulley that matches the tractor's belt width, this is best in both cases.

I would still recommend you get the right JD technical Manual (OEM, used OEM, or a reprint) for your tractor serial number and use it as a guide to rewire the tractor. Consider it as a tool in your toolbox, and the first part you need for repairs. If you consider the I&T manual ask before purchase as I see them advertised as having wiring diagrams by some sellers where others say NO wiring diagrams.

 

[Badbrad59]

Thank you sir!

 

[Duner Wi]

Yes only one plug! I’ve decided to send the alternator back since it wasn’t an exact match to the old alternator! Here’s a picture of the old one!

You might be able to compare old alternator to new alternator and figure out how to wire it. From appearance of wiring on old alternator I would think it must have charged battery at one time. Your factory installed charge indicator light has too small a bulb to excite a Delco alternator.

 

[Jim.ME]

You might be able to compare old alternator to new alternator and figure out how to wire it. From appearance of wiring on old alternator I would think it must have charged battery at one time. Your factory installed charge indicator light has too small a bulb to excite a Delco alternator.

It appears it may be an LED that can be changed to a 194 incandescent bulb which should work