JD 4020 wires melted

[TigerPaw4020]

Melted the blue and brown wires from the 24 volt solenoid on my 4020.

Insulation melted on both and the blue wire burned completely through about 6" from starter.

No other wires affected, and those wires not affected going to regulator/generator, only from connector on switch panel to starter.

I expected that I had a solenoid or starter problem, but someone suggested that it might have been low voltage only.

Removed melted wires, charged batteries, and reconnected battery cables with no problems. Then shorted across solenoid terminals and tractor started fine.

I would love to assume that this was just low voltage, or my novice teenage nephew operator, or squirrels/rats chewing on my wires, but I'm leary that there is an intermittent starter or solenoid problem that may raise its head again after I rewire.

How do I troubleshoot the starter/solenoid to be sure it is OK? What should I look for? What do the experts think happened?

 

[tim s]

Now would be an excellent time to re-wire to 12 volt....

 

[TigerPaw4020]

That for me is a completely economic issue. If I need a complete starter then maybe it will justify the cost to convert, but if it is only a $30-50 solenoid, or brushes, cleaning, etc. then no way I'm spending $500 to convert a tractor that has been working fine for 45 years.

 

[tim s]

Fight with it for a few weeks then tell me how you feel about your 45 year old 24 volt system....I'm giving you solid advice about the conversion,,economics and aggravation figured in with dependability on the plus side...

 

[Jake Winn]

I am completely agreeing with Tim on this one. Once you start having problems like that with the 24 volt system, they dont usually get better with time. We have a local starter shop that has supplied us with a good 12 volt conversion kit including a starter, alternator, some of the necessary wiring to convert it. Deere also has a kit that works well. If its something that gets used a lot, it may also be worth the investment for a new wiring harness and switches. There are some good aftermarket harnesses out there that work very well. It may take some cash up front to do it, but its better than having something short out and burn up the tractor. Which can happen to those old tractors.

 

[TigerPaw4020]

I rewired the tractor a couple of years ago to replace the brittle wires and crumpling insulation. Also cleaned all the old dirt, oil, grease. crud, etc around all the wiring, which is what actually burns if wires get hot.

Does anyone actually have an answer to my questions, or has this site evolved to only 12 volt afficiadados?

 

[tim s]

You have a short, the 2 wires that got hot are the power supply wires,,the 24 volt greatly enhances the short when it happens, start looking for rubs to start with, then start checking out the starter then the charge circuit,,a smart guy like you shouldn't have any trouble finding the problem....I'm a 12 volt advocate so I won't be much help to you...

 

[Cliff Nelson]

The short answer is "They'll do that". I know it's not the answer you're looking for. Take the starter, generator, and regulator to a reputable shop and have them checked out. See if they can determine if these components are at fault. Thoroughly check the wiring for any evidence of heat or rubbed wires. As a technician with 20+ years experience with Deeres I would recommend converting to 12v if at all possible. The wiring harness can be made with $25 worth of materials and some time if you are handy with wiring. Biggest expense is the starter. If you do decide to leave it 24v at least put the circuit breaker kit on it to protect the wiring. Let us know how it turns out.

 

[TigerPaw4020]

Tim, any short that may have been present in the wiring is now melted. No way to tell if one was present before, but unless rodents chewed it it is not likely since it was all relatively new and all in wire rap.

I want to know about possible shorts in the starter or solenoid and how to check for them or for brush dust shorts?

What should the ohms reading be between the various solenoid terminals?

Are there any checks I should make on the starter or solenoid before I tear them apart to look at them?

 

[TigerPaw4020]

Cliff, the wiring is not a problem as you say. I already rewired it once. I have plenty of wire and connectors and enough smarts to read a wiring diagram and hook it up either way 12 or 24.

If the 24 volt starter is shot, and I have to replace it, then that cost can be applied to a 12 volt starter and alternator, and I would consider converting.

What I need to determine is if it is truly shot or just needs minor parts, repairs or cleaning, or if it is just a temporarily stuck solenoid? Is there a way to do that with simple volt/amp/ohm meters or does it require sending it to an electric shop?

 

[Tx Jim]

If you're mind is made up to keep it 24V's then put the breaker kit on it that Cliff recommended & also JD recommended years ago. Or you'll probably some day find a fire under the dash and also get to rebuild steering valve & dash components. Then that 12V conversion that Tim referred to will be "look cheap" compared to repairing that fire damage. I've seen several 24V tractors burnt that way before JD introduced the kit.There may be cheaper breakers that will accomplish the same as those listed.
2 AR47710 BREAKER,CIRCUIT ADD 66.15 USD 132.30 USD
1 R45642 BRACKET,CIRCUIT BREAKER ADD 13.91 USD 13.91

 

[tim s]

There are a lot of "ghostly" problems that accrue in 24 volt systems, a simple feed back in a light switch can cause wires to cook, as well as in the ignition switch, then there is the problem of dealing with adding a monitor or a radio to a system that is un-friendly to them, I won't repair a 24 volt system here anymore,,not even for my Mother,,I switch it all over with new switches and gauges, wiring and all and the customers drive away happy as clams...and it will stay fixed for a long time...

 

[TigerPaw4020]

I understand Tim. The lights circuit is completely removed on this tractor for that reason. The only thing on it is the key switch, starter switch, regulator, generator, starter/solenoid, oil and gen lights, and fuel guage/sending unit.

When I bought the tractor a few years ago, none of the lights worked and the wiring was a disaster, so I took it down to the basics to get it running. I found I haven't needed any of that stuff so I just left it off, since it makes it much simpler, safer, and the batteries stay balanced longer.

The only thing that I can think of that I removed that may have been a mistake was the fuse in the chassis ground between the batteries, and that wire is probably too big to be a fusible link, but I thought since there were no lights it would not matter. I don't know if it did or not, but probably not since the wires that melted, blue/brown are the +/- 24 volt wires straight from the battery connections on the solenoid.

My guess is that the solenoid contact washer hung up for too long and didn't release due to low voltage when my nephew released the starter button, or he, being a complete novice (first day ever driving a tractor), may have held it too long.

Is the circuit breaker that you mention the two 20 amp ones on the switch panel between the key switch and the light switch? If so they are removed also as that is where I disconnected the power to the light circuits? I'm guessing that you are tallking about an additional breaker, but I will have to do some searching and reading to figure out where it goes in the circuit.

I was just hoping that there was some diagnostic checks that I could make to see if it is a bad solenoid. bad starter, or just a temporary low voltage that caused it. Since it now works again, it was probably just low voltage, but I wanted to check just to be sure.

Thanks for your help.

 

[Tx Jim]

[/quote]

No the circuit breakers I posted the numbers of are larger and mount on a plate on the starter and the brown & blue wires attach to them.

 

[larryanderson]

I have seen first hand the damage a 24volt melt
down can cause .Tim S. is very sharp and his advice
is right on.I would fix it right and hope it lasts
45 more years.

 

[TigerPaw4020]

Thanks Jim. If the starter/solenoid is OK, I will add those for a little more safety factor.