24 volt fun

8850dave

Member
I am working on 1965 JD 4020 with the 24 volt system just trying to get fuel guage to work then maybe check out the lights but boy oh boy its driving me crazy. The tractor has original wiring harness that is in very good condition, but when I put circuit tester point on platform and scratch it and other end attached to the positive post on RH battery the test lite lites up omg. I do have a JD service manual studying the wiring harness but still now power to fuel guage and I did put on a new ground wire from the LH battery so I am thinking I need to remove the operators platform to see what is rubbing underneath. Also sometimes I have power coming to the 2 circuit beakers mounted on the switch panel then next time I do not. The tractor has sat about 5 years and I am just trying to get it ready for use this summer .
 
To test the gauge unhook the wire and ground it with the switch on. The needle will go to full if the gauge is good. If the needle doesn't move the gauge is bad. The sender is a rheostat on the ground side.
 
I tried that many days ago but still you need power to the switch first then I had power when I put test lead into wire from the sender and it was not hooked to anything but the sender so I removed the sender and installed a new one from Jerry's and will install a new guage from him as well.
 
I am still not sure why anyone would fight with 24 volt systems for even 1 hour ??? Other than Personal self inflicted Misery..
 
(quoted from post at 08:15:19 03/10/17) I am still not sure why anyone would fight with 24 volt systems for even 1 hour ??? Other than Personal self inflicted Misery..

I agree 100%. I understand JD's 24 volt system better than the majority of tractor owners and if I owned a JD tractor that came with 24 volts it would be changed to 12 volts before it got used.
 
Dave, It is NORMAL for a test light to light if placed from either the left or right battery to the chassis. This is a test for the integrity of the small middle wire. If the light did not light it would indicate that the wire was missing, corroded, or broken. Deere used the 24 Volt system for 11 years. You would feel foolish spending hundreds of dollars to change to 12 volts if you have a minor problem.
 
Part of the dash is 12 volts NEG ground and part is 12 volts POS ground. Note - tractors have no real "ground" regardless if 12V or 24V but I am calling "ground" the main tractor frame. The fuel sender works just like they do on a 12 volt tractor. Is your oil-pressure warning light coming on?
 
(quoted from post at 08:37:54 03/10/17) Deere used the 24 Volt system for 11 years. You would feel foolish spending hundreds of dollars to change to 12 volts if you have a minor problem.

IMHO JD utilizing 24 volts for 11 yrs was 11 yrs too long. It cost about $400 to change from 24 volts to 12 volts. IF a person with a tractor with 24 volts discovered that the wiring had shorted out under the dash which created a fire that $400 conversion would appear very minimal. Yes I've seen several tractors with 24 volt systems that caught fire under dash & not all JD tractors with 24 volt systems had circuit breaker kit installed.
 
For starters, the power terminal on the gauge (likely labeled "IGN") should measure (-) 12 Volts (nominal) with respect to the gauge housing and tractor chassis with the key switch "ON".
 
I was working on those tractors in the 60s-70s at a Deere dealership when they were "current" (no pun intended). We certainly never
converted one for $400 - not even back then. I also do not recall ever seeing one that burnt up anywhere unless someone modified the
electrical system. There were always fuses and/or breakers. Deere had three 24 volt systems I worked on and went to many Deere service
schools on the subject. The Dubuque 24 volt system used in 1010s. Also the Waterloo system being discussed here that was a split AC Delco
system with 24 volt starting and charging, and two 12 volt sub-systems. With that - there were at least two versions. Some had a grounded
cross-over cable and some not. Biggest problem with the system was usually created by the person working on it and making things worse.
Biggest genuine problem was starter-motor dust polluting the inside of the starter and making it lose its isolation to the tractor frame.
That and current-draw inbalances between the two batteries.
 

JDEM
I didn't state convert from 24 volt to 12 volt back in the 60's-70's I meant TODAY!!!!!!! Here's the parts listed below from this(Yesterday's Tractors) website.

46490.jpg

I was also employed by a JD dealer from '66-'87 & I can guarantee you JD Waterloo built 24 volt tractors caught on fire & burnt under the dash. That is the main reason JD introduced the circuit breakers that mounted on plate at starter & wiring harness kit
 
Dave, there are A and B 12 volt feeds up to the switch. One is 12 volts (fed off - terminal of one battery) the other is 12 volts (fed off + post of other battery) as an attempt to balance the 12 volt loads like the lights and gauges etc. by feeding some off the A and others the B feed.

Contrary to what someone once posted, the 24 volts IS NOT POSITIVE GROUND. The starter and generator are two wire 24 volt isolated from frame devices NOT Positive and NOT Negative grounded.

Its such a rats nest, lots of wires in a small space, and colors faded its tough to troubleshoot if you don't know what you're doing and have a complete schematic.

There can be a small jumper wire, maybe or maybe not fused, where the two batteries tie in series in the middle that goes to chassis/frame.

That dual hybrid 12/24 system was NOT Mother Deeres best design lol

John T
 
No problem John, AC Delco or Delco Remy??? I would have to go check the exact history, I'm not sure myself, it still was a poor system in my opinion regardless of Mother Deere or Delco whomever lol

Take care and God Bless, keep warm up there in Michigan or New York I'm having to run my AC today in Florida yayyyyyyyyy

John T
 
Jim as both a used tractor dealer and farmer back in the day I have to agree that system had some problems and its even worse now that its old. Farmer Billy Bob and Bubba who were electrically challenged had problems maintaining it for sure. Maybe Deere dealers and mechanics who were familiar with and worked with it got along okay but many farmers were out to lunch on that system lol

John T
 
(quoted from post at 13:45:07 03/10/17) Correction - to be technical, I guess they were called Delco Remy back then.

It's really immaterial who designed the 24 volt electrical system JD engineers utilized on Waterloo tractors because any 12 volt system is much better & a whole lot less complicated!!!!!!!!
 
It sticks in my head because the John Deere guys who taught the training schools in Syracuse made a big point about the system NOT being designed by Deere engineers and Delco was paid for it (and to be blamed for it). The 24 volt system used in 1010s was much better and I kind of wonder why Deere did not use it in the Waterloo tractors.
 
My 1956 Allis Chalmers has a 24 volt system and it is every bit as simple as any 12 volt system.
 
Neat story sounds like Mother Deere was already sayin DONT BLAME ME BLAME DELCO imagine that LOL

John T
 
Ok you guys convinced me to convert I have plenty of 12 volt starts just need an alternator and where would I buy the magnetic starter relay and send me a wiring diagram , I did one about 10 years ago on my favorite 4020 power shift and I have a couple of others that I bought that were already converted.
 

JD offers a relay that's not too expensive. I hope your 12 volt starter is built strong enough for a diesel engine.
RE164448 RELAY, STARTING ADD 25.37 USD

46506.jpg
 

Oh now! Them JD 24 volt systems ain't that bad.....

A big part of the issue is the age of the machines now...parts are rusty/dirty/greasy...connections are probably rusty and crusty...wire harnesses rotten...plus it's a strange deal to work on for somebody use to 12V negative ground systems 'cause you essentially have a 24 Volt isolated starting/charging system and one 12V negative ground system and a 12V positive ground system....

I've seen you guys get into rather 'spirited' debates over just how John Deere's antiquated 24V system works!...
 
"Them JD 24 volt systems ain't that bad.".... Is like saying The manure is not that deep ,,as you walk out on a crusty lagoon ;^)
 
Sir, You are correct good chance, most often it's not that it was a 24 volt system was the problem, rather its more that it just needed repair from age and wear and tear or correction from people working on them that shouldn't been. Working and repairing these simple 24 volt systems is no different than working on any other part of the tractor. If you don't understand how they work you won't be successful or able to repair them. I just sent home the second 4010 I had split for repair in the last month and both still had their original 24 volt systems working like the did when they left Waterloo when new. One had the original wiring harness with individual ground straps on it! I never convert them unless its strongly requested by owner and fix/repair 90% of these systems and been doing it for 40 years. They are different but not complicated. Not the best for adding electrical options that draw significant amperage. Battery loads need to be kept in balance. Everybody to their own but, If I owned a tractor with this system it would stay 24 volt. DW
 
(quoted from post at 18:56:11 03/12/17) "Them JD 24 volt systems ain't that bad.".... Is like saying The manure is not that deep ,,as you walk out on a crusty lagoon ;^)

LOL!!! :lol:

Several yrs back a visitor at local dairy drove their new pickup down feed lane then attempted to turn around in manure holding pit at the end of freestall barn. Needless to state new pickup SUNK IN POOP.
 

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