John Deere 4020 Electrical Problem

[cornstalk]

Hello all,

Have a problem with my 4020.

This past summer - if the tractor sat for more than 2-3 days...it wouldnt start. At the time - was a 24v system.

1st thing I did was replace the battery's - 2 brand new JD 12v's.

Seemed to help for awhile - but not long and was back to not starting if sat for more than a few days.

After many suggestions to switch the tractor over to 12v- I bit the bullet and bought the kit. Switched her over didnt seem to have any problems. Followed the enclosed directions. Hooked the batteries up parrallel (Both pos to starter - both negs to tractor frame)

Same thing - accept seemingly worse now. Tractor sits for one day..and it wont start. Hmmm.

Started some trouble shooting. Hooked up a load tester. Both batteries showing 12-13 volts after a charge. Unhooked the red/white wire clip that goes into the alternator - checked with test light.....red = light, and white = dim light. To my understanding - with the key off....my white wire should be dead. So seem to have some stray voltage here?

Went up to the key - all spades on back side are used. 3 of the 5 are hot with the key off. (one is quite a bit dimmer than the others)

Is this telling anybody anything? I dont have a clue where to go next....but getting tired of having to boost every time I need to start the tractor. (Start every 3-4 days to fill a hayfeeder)

Thanks for any insight.

 

[llcupit]

Check the switch with an OHM meter. You will need to unplug the wires to do so. The switch could be bad. Had one go bad on a 3020 and it would drain the battery in no time.

 

[larryshoat]

I think your right about that white wire. I think the white wire is in the alt light circuit and should be dead with the key off..
I could check one of ours tomorrow.

Larry

 

[hillrancher]

Cornstalk : Did you change the alternator when you went to the 12V?

 

[cornstalk]

You bet - brand new alternator, and starter.....new ground cables also.

Appreciate that Larry. I think the white wire is at least a portion of my problem. Just cant figure out why or how.

Keep the ideas coming.

How do I check my switch with an ohm meter? Have one around - but not real sure how to use it in this manner.

Thanks.

 

[Rangenerd]

put in a battery disconnect. It will stop then bleed off and is a hell of a lot cheaper than replacing all the components.

 

[WHITEHAWK]

put in a battery disconnect.

It will stop then bleed off and is a be nice of a lot cheaper than replacing all the components

I like this idea,short and sweet..............but if you want to try and find the problem,what I do is when its dark,take one of the battery cables off the battery,scrape it on the battery,if you see some small arching,you know you have a short,should'nt be any archs with everything off,then just start disconnecting wires one at a time,till you lose the arching at the battery

 

[hillrancher]

Corsnstalk: By elimination you can isolate the problem. Take the battery cable of take a volt meter from the post to cable to see if you have a reading with every thing off. If so you have the short or flow to ground. If you do go to the fuse panel start removing fuses until find the short or, then that is the circuit you have to work on. Alternator may not have a fuse not all do disconnect the battery wire off or feel of the alternator after the tractor sets and cool to see if the alternator is worm.
Do you have a light or a meter to tell if the alternator is working?

 

[cornstalk]

I have a test light, a load tester - and an ohm meter I dont use too often (not real sure how to use it).

I tested the Alternator via putting my load tester on each of the batteries with the tractor running. Showed 14.2v on both sides. I think the alternator is ok.

You want me to put my volt meter between the pos cable and the pos post (with cable unhooked)? I can try that - should read zero? What setting should I have my meter on to do this?

Thanks for the help guys.

 

[larryshoat]

I have a test light, a load tester - and an ohm meter I dont use too often (not real sure how to use it).

I tested the Alternator via putting my load tester on each of the batteries with the tractor running. Showed 14.2v on both sides. I think the alternator is ok.

You want me to put my volt meter between the pos cable and the pos post (with cable unhooked)? I can try that - should read zero? What setting should I have my meter on to do this?

Thanks for the help guys.

I checked one of ours the white wire should be dead with the key off. There should be a wire from the switch to the gen light then from the gen light to the white wire on the alt hookup. When the alt starts to charge the white wire loses it's ground from the regulator and the gen light goes out. Sounds to me like that switch is bad.
That's a good idea about connecting between pos cable and post. I just use a test light , most of those meters are so sensitive they will pick up voltage on one that is working right.

Larry

 

[cornstalk]

Thanks for checking that Larry.

Definately part of my trouble. Replacing the switch is easy enough - and not so costly...I may try that first.

One thing - if that white wire runs through the bulb - prior to the switch ....and my white wire is showing a dim light on my test light at the alternator - shouldnt the gen bulb be lit up also?

I did pick up a couple of swan disconnects at Walmart today - $3 a piece. I'll put those on my neg terminals - so should at least prevent the drain off.

I'll replace the switch in the coming days and post back what becomes of it. Thanks for the ideas guys - anybody else has anything let me know.

*Edit - just called deere, $40 for that switch. :shock:

Thanks!

 

[cornstalk]

Thanks - I'll try that.

Think I may have other problems also? Even after sitting for 1 day with my batteries isolated. (Checked prior to getting in and starting - 12.3 volts on my meter) Get in and hit the starter - seems like I'm only getting half of the power I should be to the starter - slow to crank, not quite enough to make er fire.

I may be over my head here.

 

[hillrancher]

I have a test light, a load tester - and an ohm meter I don't use too often (not real sure how to use it).

I tested the Alternator via putting my load tester on each of the batteries with the tractor running. Showed 14.2v on both sides. I think the alternator is ok.

You want me to put my volt meter between the pos cable and the pos post (with cable unhooked)? I can try that - should read zero? What setting should I have my meter on to do this?

Thanks for the help guys.

Should have your volt meter set to the next higher setting than the voltage you are testing to protect the meter, but since this is 12v DC set at 12v is ok. You should not get a reading with every thing turned off. If you are getting a reading you have a problem then start isolating, by pulling fuses.
The white wire is the exciter wire for the alternator I am thinking. It should have a light in it for a resistance which is on the dash to show if the alternator is working. This white wire kick in the regulator.
Do you have an external regulator or internal?

 

[cornstalk]

Is this the regulator thats on the starter? My 12v kit included a starter with a regulator mounted on the side of it. Dont know of any other regulator.

I did notice a "black box" located right above where the alternator sits - up under the hood. But didnt appear that the white wire went into it. (White wire disappears into a harness which runs up towards the fire wall)

I dont have a fuse board on this tractor that I know of.

 

[larryshoat]

Is this the regulator thats on the starter? My 12v kit included a starter with a regulator mounted on the side of it. Dont know of any other regulator.

I did notice a "black box" located right above where the alternator sits - up under the hood. But didnt appear that the white wire went into it. (White wire disappears into a harness which runs up towards the fire wall)

I don't have a fuse board on this tractor that I know of.

The part on the starter is a relay. On ours I moved that so I could reinstall the side shield without bending it. The black box that is above the alternator is the old regulator for the generator. Most of the alternators in the kits were Delco 10 SI
and they were internally regulated. They use cicuit breakers instead of fuses they are on the panel where the switch is mounted.

Larry

 

[luke strawwalker]

Sounds like a bad regulator or isolation diode. Disconnect the battery cable and hook a test light between the battery post and cable end. The test light should not be lit with the switch off. If it is SOMETHING is drawing power and that is killing your batteries. Just disconnect stuff until the light goes out and when it does you found your culprit. Good luck! OL JR

 

[novatech]

Corsnstalk: By elimination you can isolate the problem. Take the battery cable of take a volt meter from the post to cable to see if you have a reading with every thing off. If so you have the short or flow to ground. If you do go to the fuse panel start removing fuses until find the short or, then that is the circuit you have to work on. Alternator may not have a fuse not all do disconnect the battery wire off or feel of the alternator after the tractor sets and cool to see if the alternator is worm.
Do you have a light or a meter to tell if the alternator is working?

Great advice.
But wouldn't you use an ampmeter between the post and cable?
This is the only way to find your problem.

 

[KenB]

Thanks - I'll try that.

Think I may have other problems also? Even after sitting for 1 day with my batteries isolated. (Checked prior to getting in and starting - 12.3 volts on my meter) Get in and hit the starter - seems like I'm only getting half of the power I should be to the starter - slow to crank, not quite enough to make er fire.

I may be over my head here.

You should have more voltage with a fully charged battery.
Seems like you have a battery problem.

 

[cornstalk]

Ok - You've given me a few things to try...I'll let you know what I find out.

Thanks for the ideas.

 

[larryshoat]

Thanks - I'll try that.

Think I may have other problems also? Even after sitting for 1 day with my batteries isolated. (Checked prior to getting in and starting - 12.3 volts on my meter) Get in and hit the starter - seems like I'm only getting half of the power I should be to the starter - slow to crank, not quite enough to make er fire.

I may be over my head here.

You should have more voltage with a fully charged battery.
Seems like you have a battery problem.

That deal in those kits to get the battery hooked parallel is poor at best.
That connection is always going bad ( dirty). I would clean that and see if that solves the slow cranking speed. I don't know how that disconnect works , but generally speaking the more connections you have the harder it is to keep working.
On one of ours I had a new cable made up and on the other one I just took two cables all the way to the starter.
Sorry about your trouble I know it gets confusing, but at least it is easier than that old 24v system.

Larry