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Auto 18. Help rewiring ignition after electric fire.

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Well my '73 auto 18 was running great yesterday until the engine died and quit.  Next I see smoke rising from under the hood.  There was short in the wire harness and wire was burned right to the copper. I reached in and was able to stop the tractor from goin up in smoke. I just ripped out the shorted wire harness and it stopped.  So i took out the battery and went to work.

I looked at the wiring diagram, which seems straightforward until you try to match it up with the ignition switch.

After spending a couple of hours rewiring, I can not figure out which wire goes where in the ignition.

Can any one help me as I am totally at a loss.  The letters on electrical diagram  around the ignition sketch don't match anything i see on the actual ignition.

Would anyone be able to give me a hand. I don't need to compound problems by experimenting with wire combinations on the ignition.

Very grateful for any help.

Thank you.






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Download this file

The one you want is named
WH61-90 #134 Ignition switches 1972b.pdf

The original ignition switch 101917 was replaced by another shown on the last page. I think that will help and being in pdf format you can print out that page.


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Hi Gary,

Thank you so much for the quick reply!  Even though it's a 73', I guess '72 switch models being used would make sense.

I'm going purely by comparing visually the graphic to the actual ignition tab connectors. I guess this is the one that seems to best match up with what I have.

I just love this forum. It has helped me so much. It's wonderful :) I'll give it a shot putting the wires where they say they should. Hopefully it won't go boom!




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Once you get it figured out there is a connector available that takes the guess work out of it next time. This one is supplied by Stens
or it is available with wires in each cavity

If you don't like the wire color locations the terminals can be released and inserted where you want them. A 1/16" or 3/32" cotter pin opened up makes a good terminal release tool. Can explain how it is done if you don't know.
Napa also has this harness and they likely have the bare connector also.


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Hi Gary,

Thank you so much for the quick reply. Even though it's a 73' I guess '72 switch models being used makes sense.

I'm going purely by comparing visually the graphic to the actual ignition tab connectors. I guess this is the one.  

I just love this forum. It has helped me so much. It's wonderful :) I'll give it a shot putting the wires where they say they should. Hopefully it won't go boom!


Well, guys thank you again for the help! Inside of a few minutes got the wires back in place on the starter and she started right up!

No way I could have done this without those helpful schematics. The owners manual just didn't cut it.

So thank you and best to all!

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