John Deere 4320 - Electrical problem, will not start

So last year we had an issue where the tractor key had to be turned around 20 times for it to actually engage, as if after many tries you got lucky. It would just click from the relay above the circuit breakers. This year after charging the batteries (Converted from 2 6volt to 2 12volt)we were having the same issue, only this year the starter will not engage. The closest we got ever dozen or so turns was a very slow turn of the starter and a loud rapid "Click click click click". Again this only happened every so often. We have replaced both the relay above the breakers and the starter relay. We took the starter and solenoid off and had it tested at a nearby shop. The worker seemed very knowledgeable and said when he tested it he had no issues. We put the starter back on after cleaning the connections in multiple places on it and the relays. Still no improvement.

We finally decided to pull the key switch and the connections looked very rough. We did our best to quickly clean with a wire brush but again no luck. Upon re connection the system bugged out and blowers would not work and all accessories began acting up, we believe that we may missed a connection but begin frustrated we gave up for the night. I am just including this info in case it may mean something.

So in summary our starter and solenoid were tested to be working. We replaced both relays and still had no luck. We are now planning on replacing the key switch.

I believe we tackled this issue without much organization or logical diagnosing. Electrical is by far not our strong point. If anyone has any suggestions or tests we would greatly appreciate it. We need this tractor in the field ASAP and would love some help. I can provide any additional information or clarify anything that comes up. Thank you

We had problems that resemble yours. Replaced the ign. switch. End of problems.

Had a 4320 do the same thing 4-5 yrs. ago. Had new batteries and a new key switch. Started and ran outside, shut it off and went to start it an nothing. Turned the key on , the dash lights came on and when you turned the key to start, the starter would click and then the lights went out and everything was dead. No lights radio or anything. It ended up being the ground cable on the batteries at the frame. Looked like new but when I twisted it, the end came off with very little effort. It was corroded inside the end of the cable and until it broke off you could not see the corrosion. The batteries and cables are a real pain on those especially if it has a cab. Take the platform off or the floor out of the cab is the easiest. Just what I found on mine but in the end I will bet you find a bad ground some place. Good luck

Mr.Andrew380
Welcome to YT
Ditto on replacing key switch. Does relay above starter have a good ground connection. Have battery ground cables that connect to tractor been cleaned/tightened?

If you hear it clicking it's probably not the key switch, ,,most likely its the starter relay mounted above the starter on the fire wall..The contact area inside it gets burnt spots on it and will not let it complete the circuit to the stater..

Bad battery cables will do that.

All good advice, I had a 3020 once where the battery ground connection at the tractor casting was bad. It looked connected but the corrosion had stopped current flow. Sometimes people connect the battery ground up at the starter mount. Just a thought.

Regardless where the battery ground is, also make sure the starter mounting will pass current. I have already put the star washers under the starter mount bolt heads after cleaning that interface up real good.

I kinda lost track of what was replaced and what was left. I was thinking key switch but Tim and Tx likely have a better idea. I would also check the grounds on the relay.

Paul

The ONLY way to diagnose electrical problems is with a voltmeter! I published an article entitled "My Tractor won't Start, What will I do?" in Green Magazine a few years ago. The article gives a detailed procedure in how to use a voltmeter to troubleshoot a cranking problem. Parts replacement is very foolish and expensive, but the voltmeter will pinpoint the problem.

I agree and have no idea where people are so scared of a multimeter . Nor why they have no problems guessing and throwing random parts at a faulty machine .

Yes, a loose, poor, or no ground will certainly cause that. That's where its nice to have a multimeter that can check voltages and continuity.

Decades ago when I was building boats, one time I was missing the ground and current was feeding through the 14 or 16 gauge dashboard wiring to the batteries. I shut all of the lights off in the shop and looked around and noticed a glowing coming from the distant corner. At first I thought it was a fire, but it turned out to be the dashboard gauge lights dimly lit, acting like the ground as current fed through them to get to the positive terminals on the batteries. I opened the battery switches and dealt with it the next day. No main ground, and current to the least resistance and only path to voltage...through the gauges.

Mark