4020 jd batterries

Hi Fellas ,,. 5yrs back , had a friend switch the 4020 over to 12 volt ,,usin the jd kit ,,ever since the volt meter reads a nea@tive char@e ,,we have recheked wirin@ many times..i believe there is zero char@e to the batterrries while runnin... in those 3 yrs that deere went thru at least 3 sets of batterries... certainly need a more qualified mechanic to look this problem over.. also,, lol , minor problem my G on the computer keyboard reqires 20 pounds of pressure ..and i cant locate my readin @lasses this Am , ,,mornin eyesite is a bear for me

I'm not familiar with the JD kit. Does kit include a different wiring harness or just instructions to alter existing wiring harness? What type of alternator? When you state zero charge is this at the alternator?

j hikemper

I don't know if this link is any help


Alont
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JD 4020s did not have an ammeter. They had a charging indicator light. If that is what you have there is a diode that you have to remove to get the indicator light to work. To energize the alternator you have to change the wiring that went to the generator/regulator. I also usually remove the voltage regulator. It is not used and is easier to wire around if it is taken off.

Have you taken a volt meter and check to see what voltage is at the batteries when the tractor is running??? A bad alternator can over charge the batteries and that will make them go bad faster. If you have low voltage then the starter usually cranks slow.

I will try to walk you through the wiring changes you need to do. The two wires that went to the circuit breakers on the dash get hooked together. They used to be: one positive ground and the other negative ground. They charged the two batteries to make it 24 volt. These two now provide the wiring that the alternator uses to charge the batteries.

The other wires that went to the regulator are what you use to energize the alternator. Take a volt/ohm meter and find the one that is hot when you turn the key on and off. This one usually had a "L" shaped diode in it. This gets hooked to one side of the alternator. The other factory wires are not used.

To the other terminal on the alternator. You make a short wire that goes under the battery terminal on the alternator on one end. The other end goes to the other small terminal on the alternator.

Most of the time the fuel gauge will need to be changed too. The original one was on the positive ground circuit. It will not work after you change the system over to completely negative ground.

Email me if you need more help. There where several different wiring harnesses used on the JD 4020 24 volt diesels. They where a little different but not much different.

(quoted from post at 10:45:44 12/04/11) The two wires that went to the circuit breakers on the dash get hooked together.

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JDseller
IIRC the 2 circuit breakers under the dash were for the head & rear lights. Wouldn't it be simpler to just be sure both Batt A & B supply wires were tied together?? If tractor has had the update kit with circuit breakers on a plate that is secured to the solenoid mounting screws then be sure they're both CB's are powered by 12Vs

TX Jim the battery A and B wire was what I was telling him to hook together. They go to the circuit breakers under the dash but they power everything on the tractor not just the lights. The power goes to the two power terminals on the key switch.I am not explaining this very well.

As for your other posting you have too modify the wiring harness. There is not a kit I know of to just plug it in and go. There are several serial number breaks on the wiring harnesses on the JD 4020. I think that there are four different diesel harnesses.

It is not hard to change the harness but you need to under stand what you are doing. It is not a job for someone that is not familiar with the how they are wired. The original 24 volt system was kind of an oddity in itself. I never like the way it worked. Everything had to be perfect or the batteries would not stay balanced.

I remember having to wire in a light bulb on the positive ground system when you put a negative grounded radio on the tractor. If you did not the one set of batteries, in a long day, would discharge.

JDseller
What I was referring to is attaching both the brown & black supply wires(which are the Batt A & B supply wires) at the starter together to the positive cable therefore there would be no need to alter the wires on the circuit breakers under the dash. This doesn't address the voltage regulator,fuel gauge or idiot light because I agree with what you stated earlier about those items. Please correct me if I'm wrong as it's been many years since I was a JD service manager.

If I'm looking at the parts catalog correctly for an open station 4020 diesel < SN 200,999 there's only 2 main wiring harnesses. This doesn't include the different harnesses for powershift & Syncro-range trans which are different because of the safety(neutral start) switches or the lamp harnesses.

MAIN WIRING REPLACEMENT KIT(NOT ILLUSTRATED)
(DIESEL)(TRACTOR SERIAL NO. 065000-090999)
AR44954 WIRING HARNESS 1 (SUB FOR R39645) (SUB AR47662 KIT)

GENERATOR AND STARTER WIRING
(DIESEL)(TRACTOR SERIAL NO. 091000- )
AR47697 WIRING HARNESS 1 MAIN

Thanx Fellas,, You Gave me a wealth of info to study ,,. wisht you all lived nearby ,,