JD 4020 24v Questions

[wore out]

What is your serial number, early (pre 91,000) 4020's had one of the cables from each battery connected to the chassis. (20 and 21 in the diagram below.)

Later models had a crossover cable and the little jumper to the chassis for safety from electrical shorts starting a fire. Lots of older tractors were updated, as well.

I ASSUMED you had the version with the crossover cable.

 

[Tx Jim]

(quoted from post at 13:50:31 04/10/23)

Just looked when I was home and didn't see anything connected to the + terminal except a wire I have attached there for my planter marker control box. [/quote]

If you have been using your planter that's one reason you're having battery problems. JD 24 volt systems with two 12 volt batteries require for load on each battery to be equal or very near equal OR the batteries can't be charged correctly by generator.

 

[cfk]

What is your serial number, early (pre 91,000) 4020's had one of the cables from each battery connected to the chassis. (20 and 21 in the diagram below.)

Later models had a crossover cable and the little jumper to the chassis for safety from electrical shorts starting a fire. Lots of older tractors were updated, as well.

I ASSUMED you had the version with the crossover cable.

77771, so a 1964. I'll have to look under the foot plate, but I'm 99% sure the batteries are connected with the crossover cable.

If you have been using your planter that's one reason you're having battery problems. JD 24 volt systems with two 12 volt batteries require for load on each battery to be equal or very near equal OR the batteries can't be charged correctly by generator.

I haven't used the planter at all since last spring. Good to know that I might want to get power to that box some other way. I didnt figure it would matter much since its just the actuator that changes the marker selection from one side to the other.

 

[cfk]

Should be from the (+) battery terminal on the LH battery to the chassis.

Either a length of fusible link wire or a fuseholder with a 20 Amp slo-blo fuse.

Don't confuse it with the accessory power lead from the (-) post.

Pulled the floor plate off this evening and see where the ground wire is bolted to the chassis, but its definitely not connected to the battery. There is a half of a slo-blo fuse holder, but the other half and wire (to the battery) is missing.

I will definitely fix it tomorrow, but is that what is causing all my problems?

Does it have to be fused? The schematic you posted doesn't show a fuse on there. In case I can't find a slo-blo fuse in town, can it be a standard automotive blade fuse?

Thank you guys again for all the help.. I apologize for my ignorance!

 

[wore out]

Replacing the centerpoint ground wire we are talking about isn't going to solve your dead battery problem, but it's a good idea to do so.

It makes the fuel gauge read accurately and helps keep the voltage to each half of the lighting circuits relatively equal.

The latest and greatest solution DEERE offered was a length of 16 or 18 GA fusible link wire with eyelets attached, R39713, nla from DEERE, but you can get a link without the large ring terminals at an auto parts store and make your own.

Once again, I suggest having your batteries load tested.

 

[cfk]

It makes the fuel gauge read accurately and helps keep the voltage to each half of the lighting circuits relatively equal.

The latest and greatest solution DEERE offered was a length of 16 or 18 GA fusible link wire with eyelets attached, R39713, nla from DEERE, but you can get a link without the large ring terminals at an auto parts store and make your own.

Once again, I suggest having your batteries load tested.

That's awesome. The fuel gauge hasn't worked for a little while, so that's cool that its likely an easy fix.

And I'll have the batteries load tested sometime!

 

[wore out]

(quoted from post at 04:59:15 04/11/23)

The fuel gauge MAY have been damaged by overvoltage with the center point ground missing, or the sender may have shook apart over the years so installing the ground may not fix the issue, but FOR SURE you want the ground installed before installing a new sender and/or gauge.

 

[cfk]

(quoted from post at 11:18:15 04/11/23)

(quoted from post at 04:59:15 04/11/23)

The fuel gauge MAY have been damaged by overvoltage with the center point ground missing, or the sender may have shook apart over the years so installing the ground may not fix the issue, but FOR SURE you want the ground installed before installing a new sender and/or gauge.

Put the new ground wire on it when I was home at lunch and the fuel gauge works perfectly now.. thank you!

I need to get the batteries load tested, but I'm still baffled by the fact that it cranked over like the batteries were brand new and fired right up last week (after sitting in a cold shed for 6 months), and I drove it a quarter mile, parked it in the shop, put the trickle charger on it a couple days later for one night, and haven't been able to start it without jumping it since.

It will crank over now, but very very slowly. It doesn't click like a dead battery though..