Farmall Super A 12v wiring

Luke0927 · Apr 10, 2014

I have a Farmall Super A that has been in family a long time I used it as a nice garden tractor. I'm trying to rewire up the switch. It looks like it is all factory I its a 3 terminal key switch does anyone know where I can find a current diagram? The ones I seemed to find were from old sites not still active. Thanks!

Luke

Janicholson · Apr 10, 2014

I do not think Super C tractors had a Key start. It would require a starter relay (solenoid) to be used on the starter, (not hard to do) and a wire from the S terminal on the Key switch to the S terminal on the relay. I have included the diagrams from Bob M which should be correct for a C or SC. The info also covers alternators. A 12v generator system is the same as a 6v. Jim

Luke0927 · Apr 10, 2014

This is Super A, it all works currently, but I think the switch is shorting out or I have a bad connection, a lot of grime and oil and I"m wanting to trace it out and clean all the terminals. Was hoping to just find a diagram where I could compare itall

Luke0927 · Apr 10, 2014

Also it all looks factory, also has the dial switch for headlights wanting to check and get those working as well, be nice to find diagram for it all

Any help appreciated thanks folks!

Janicholson · Apr 10, 2014

Super A and Super C all had the same wiring. A very late Super A1 (not a common tractor) might have had a Key, but I do not think so. If it works, clean it and make a diagram for it as it is wired. then replace wires as needed. It was not 12 volt. Jim

Luke0927 · Apr 10, 2014

Do you know how you can check the years, or where the SN is if that's whats needed maybe this is a A1. I have looked online and the switches I saw were not key models also. The switch is pretty old and says made in USA has 3 terminals. Coil, AMM and ACC.

Jim Becker · Apr 10, 2014

What JAN said in the first place applies to the Super C, Super A, Super A1 and several other models newer than any of them. Your tractor did not originally come with a key switch.

This is a perfect example of one of the reasons I rarely reply to a question about a 12-volt conversion. Virtually impossible to out-guess what somebody hacked up when they did it, not worth my time to try.

CGID · Apr 10, 2014

If the switch looks factory, could IH have offered a key-switch option for security - for tractors used in commercial freight yards for example?

Luke0927 · Apr 11, 2014

OK thanks, I'm 28 an it hasn't had the 12 volt
conversion since I've been around. So must have
been done a good ways back. I'll clean it all up
trace it out and see what I can get figured out.
Might need a little help on wiring the lights
though.

Thanks.

mkirsch · Apr 11, 2014

(quoted from post at 21:15:54 04/10/14) If the switch looks factory, could IH have offered a key-switch option for security - for tractors used in commercial freight yards for example?

I am pretty sure, no.

"Looks factory" and "Looks like it's been there for the last 40 years" look pretty much the same.

Luke0927 · Apr 11, 2014

That"s true way before my time, it fits through and
screws in the collar on the panel I could just tell
it was an old switch why I thought it may have been
original.

TheDurk · Apr 11, 2014

Even the 140, later model of the same tractor, that came with a key, had only a simple two-terminal. Later, there was a key start, but that would not have been Coil, Acc, AMM. There would have been a spring return from the last position, and it would have been wired Coil, Start (Solenoid), AMM.

The keys were stupid simple. I could start mine with the screwdriver blade on my Swiss Army knife.

Janicholson · Apr 11, 2014

With a Coil terminal connected to a true 12v coil with no ballast resistor required written on it, it will be fine. if the primary resistance of the coil is about 2 to 2.5 ohms on an accurate meter, the coil needs a ballast resistor.
The ACC wire goes to radios, or accessories (or the lights if you want the key to control their on off status.
The AMM terminal hooks to the load side of the Amp gauge. (opposite the one connected to the starter switch)
Your key is no different than the original push pull switch except for the ACC terminal which you probably don't need. There will be no starter relay as your switch is not a start equipped switch, and a rod is used to start the engine.
The diagram supplied should work if it is a generator. or the Alternator supplement if Delco. 10SI Jim

Luke0927 · May 4, 2014

I ended up just cleaning the terminals and replacing the positive and ground from the current wiring and fires up an runs great...I'm going to leave it as is through the gardening season and redo it all based on the 12v conversion on here. Which is similar just the current setup is using the original wiring from the 6v.

What about this and it has been this way, when I turn the swtich on the Amp meter goes to the right for charging, and when it starts it goes to the left. If I put the volt meter on it, it is really charging voltage goes up to about 13.6v.

Is the meter bad you think? I'll see what you guys thing then tell you a couple things I tried.

Farmall Super A 12v wiring

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