JD4020 electrical issues -

History(in case it applies): Tractor had low batteries, my mother(heard all the jokes don't need them) attempted to jump, but crossed the wires to left battery. Cables got really hot. Got two new batteries it started fine.

Baled a couple acres, noticed the positive wire from left battery came apart from the eye hole that connects to solenoid. So easy fix get a new cable(old one had a rub spot in it from clutch)...and everything will be fine...nope...

Batteries are run parallel. 12 volt system, 12 volt batteries. Multi meter with left battery (From cylinoid ) and get 12 volts. Great, but not enough to start tractor.

Isolate right battery, multimeter it from solenoid and get 4 volts... Hmm bad wire I assume, for lack of anything else I use a jumper cable from right battery pos terminal to solenoid...and get 4 volts. Battery pos term to neg term gets 12(good battery). Battery from Pos term to where it grounds on tractor gets 12. battery is good, ground is good.(right?)

Measures 12 volts when the right battery cable is checked vs ground, but the moment i put it on the cylinoid, 4 volts.

So....help. Both batteries connect with the solenoid at same spot. one gets 12 volts other gets 4. Thus tractor won't start, won't even begin to turn over.

If there was a problem with the solenoid, why would left battery be 12 volts when connected, but right only 4... I am stumped...

Have the two batteries load tested.

Since this is a parallel system (so you say), either a battery is bad or a cable(s).

It's NOT rocket science!

as said,have the batteries load tested.a multimeter will show voltage,but will not show amps

Agree... but would there be a load when merely connected to solenoid. Key off....

I wouldn't think there would be a load or the battery would always be worn down...

I would replace the solenoid to rule it out and have the batteries load tested as suggested. I would see if the 4 volt battery will take a charge. Hal

Joe I dodnt have an answer for you but I sure hope you will post your findings and solution here for future reference. Good luck. MNBob

since 12v system,should start on 1 batt too,sec one is for capasity.disconnect both,use jumper cables on frame and solenoid,if still no start,either solenoid or starter toast.otherwise cable bad,multi meter only indicates if there is voltage,it wont measure amp draw.

check batt ground too for corrosion in eye or frame bolt.

Is this a 4020 that has been converted to 12, is it a late 4020 with an alternator (consol model) or is this an early 24 volt system?

1966... converted to 12 volt starter, appears to be an alternator....

(quoted from post at 12:20:16 08/27/08) 1966... converted to 12 volt starter, appears to be an alternator....

Click to expand...

Joe; On the batteries. In my experience only-- one of the 12 volts from the original 24 volt wont start it unless warm or very low compression. You usually see a large square box fixed to the frame near the starter and a large (hight cranking amp)battery similar to what would be in a cat installed for a single battery start. That is why you have the two battery system still intact, more cranking power. Try this site and just invision a 12 volt battery instead of a flashlight battery. http://www.batteryuniversity.com/partone-24.htm
Hope this helps. Bob