John Deere 4020 Electrical Problem

[Legacy38464]

I noticed you said, it seemed that you had half power starting when you had full batteries. Check with your volt meter what voltage the starter is pulling when you hit the starter. The new starter could be bad. happens.. :shock: Also there could be some feed back coming thru the solenoid causing the white wire on the altenater to have some power. I am not very familiar with the 4020 but the half poer when starting with full batteries sure has the smell of a starter, possibly ground wires also...good luck...

 

[cornstalk]

[/quote]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[/quote]

Didnt seem to bad - but maybe I didnt do correctly? The kit allowed me to utilize the two existing positive cables- I eliminated the cable that went from neg to neg on the previous system and used the two included brand new negative cables and just went from terminal to tractor frame.

In short - Both positive terminals are now going to the starter - and both negative terminals are grounded to the tractor frame.

Again - thanks for the ideas. Picked up a new switch just a few minutes ago - will install this afternoon. Will at least eliminate that possibility.

 

[cornstalk]

Ok guys - did some work on this this aft.

First off - JD sent me home with the wrong switch. (I didnt have the serial number with me - so was a 50/50 shot). Wrong switch - thats why I dont gamble.

Discovered a few things when I came home and took t he old switch apart. 1. The white wire spade was broken off from behind the switch. 2. Checked my wires for voltage with the key off- The blue, and brown are hot 12v's. I have a grey wire that is dim hot with my test light - meter showed 2v's. The rest of the wires were dead with the key off (grn, dbl black, broken white).

Interestingly - I started the tractor up and ran the idle up a little - and checked that broken white wire behind the switch for voltage - nothing...dead. Put meter on battery's with tractor running - shows it's charging - 14.2v's. ??

I also checked the current via positive terminal post - to positive cable with the tractor off. Showing a 10v draw.

The isolator switches on the batteries appeared to work in preventing the draw - as I had 12.5 volts prior to starting the tractor - and was enough to crank er over. (Had sat overnight).

I did post this on the tractors.net site also.

Let me know if any of this is indicating anything to anyone.

 

[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?

Great advice.

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

You can use either. The volt meter has to have a ground to work.( Like a light.) Amp will measure the amount of flow.

 

[Chuckie]

If you want it to crank the best it can, change the batteries out for 2- 6 volts hooked up in series postive post to starter, ground to postive on other batt-and ground to side of tractor. Two 6 volts in series have more cranking amps.You definitely have a short drawing on the batteries. Another thing to keep in mind the old system was a postive ground and you are changing it over to a negative ground system.If you get everything doing right the two 12 volts will crank the tractor pretty good. With the batteries in series you double the cold cranking amps when you hook 2 batteries parallel you only get the cold cranking amps of the amount of both batt divided by 2 . I put a relay on side of the panel just behind the starter and below the steering wheel to run all current through so when you turn the key off you kill all current leaving the postive battery cable.