JD 3029 Key Switch Wiring

OldGrayOne · Dec 24, 2018

My JD 3020 (serial number over 133,000) just shut down. I turned the switch to crank and nothing happened. I found a red (always hot with 12v) wire loose from the back of the key switch plug. There was also another floating wire coming from the ignition coil. Neither wire appear to be original and both had regular female spade connectors on them. I have attached pictures of the front and back of the plug, as well as one of the two loose wires.

I would appreciate it if someone could tell me which terminals these two wires go to.

Also, where can I find a new plug without buying a whole new wiring harness?

Would there be a problem in just removing the wires from the plug, installing female spade connectors and going directly to the switch?

I would still need to kn ow where the errant wires connected.

Thanks for any help,

Joe

Tx Jim · Dec 25, 2018

Have you attempted to locate where opposite ends of loose wires route to? The plastic plug besides affording insulation made R&R of wires from switch easier. You could check with Agri-services to see if they will sell you a plug. Wire Harness, Tractor Parts, Harness Repair, Alternator Conversion, Braided Wire (716) 937-6618

Zebrafive · Dec 25, 2018

They may have rigged up a wire for 12 volts to the coil for starting. You do not want 12 volts to the coil at all times, for running. A lower voltage is used for running, a resistor in the wire, or resistor/resistance wire to reduce the voltage. This give the points longer life.

I am ASSUMING a gas tractor.

OldGrayOne · Dec 25, 2018

Thank you, Jim. Makes sense about the insulation. The red (hot) wire goes into a wire bundle and is difficult to trace. I will check with Agri-Services to see what's available. I somehow expected you would come back with good advice. I appreciate you.

OldGrayOne · Dec 25, 2018

Thank you, Zebrafive. I did meter out the switch in all key positions and found the terminals that have continuity only during start. I am assuming the red (hot) wire goes to the only vacant slot on the plug connected to one of those terminals. I am still not sure about the wire from the coil. I did think it odd there was no ballast resister in the line. It appears to be made from one half of a lamp cord! I would just hate to connect things up and not have it pass the smoke test. Back in '67 I did that on a '65 Mustang and had to replace an entire wiring harness. I have been very careful since then.

Yes, I was remiss in not mentioning it is a gas tractor.

OldGrayOne · Dec 26, 2018

Tx Jim said:
Have you attempted to locate where opposite ends of loose wires route to? The plastic plug besides affording insulation made R&R of wires from switch easier. You could check with Agri-services to see if they will sell you a plug. Wire Harness, Tractor Parts, Harness Repair, Alternator Conversion, Braided Wire (716) 937-6618

Jim,
I spoke with the folks at Agri-Services this morning and they are going to send me a new plug with 8" of wire on each terminal for $20. Thanks for the information. They were very nice, knowledgeable, helpful folks...although, they sure do talk funny up there in New York.

Zebrafive · Jan 1, 2019

OldGrayOne said:
Thank you, Zebrafive. I did meter out the switch in all key positions and found the terminals that have continuity only during start. I am assuming the red (hot) wire goes to the only vacant slot on the plug connected to one of those terminals. I am still not sure about the wire from the coil. I did think it odd there was no ballast resister in the line. It appears to be made from one half of a lamp cord! I would just hate to connect things up and not have it pass the smoke test. Back in '67 I did that on a '65 Mustang and had to replace an entire wiring harness. I have been very careful since then.

Yes, I was remiss in not mentioning it is a gas tractor.

12v to the coil only at start is OK and may actually help starting. You just do not want 12v to the coil at all times.