Farmall C - help identify the ignition switch

A few years ago I bought a Farmall C to help a guy out who developed a disability later in life and couldn't run it anymore. I finally got started on this particular tractor after I got my other Farmall C running. I don't know if I ever had an ignition key for it or not. Anyway I need to either replace the key switch or put in a push pull switch. I do remember pulling it on my trailer so maybe I never had a key. I know it is suppose to have push/pull switch, but it had been switch over to a key switch. It has been converted to 12 volts with a Delco alternator. The switch has 3 terminals. See pictures. One terminal has a heavier electrical wire coming from the amp gauge (white). I assume that supplies the power to the switch. Another terminal has maybe a 16 gauge wire (red) that goes up to the Delco alternator. There is a heavier wire from the alternator to the amp gauge. So, would this smaller wire from the switch excite the alternator??? Finally the third terminal has a wire (green) connected that goes to the ignition. So, when you turn on the switch does power from the amp gauge terminal power the terminal going to the alternator and the terminal going to the ignition? Would this all happen with one click of the switch? I guess what I am saying is does the switch have just have off and on positions? What switch would I buy to replace this one? Would a push/pull switch work as well? Thanks.

Likely (but not certainly) the switch is a ''universal 3-terminal ignition switch'' with ''ACCY'', ''OFF'', and "ON'' positions and they used the ''ACCY'' terminal to excite a Delco 10SI (or similar) alternator.

If that is true, the simplest thing would be to get a similar, new switch.

If you can't find one that simple, one with a ''START"" position will work, just ignore the 4th ''START'' terminal and the start position.

If that is, in fact the type of (common) alternator that was used the reason they used that ''ACCY'' terminal to power the ''excite'' terminal on the alternator is to separate the ignition power to the coil and the ''excite'' power to the alternator.

If this is NOT done, power feeding back from the alternator's ''excite'' terminal into the ignition system will cause the engine to continue to run when the key is switched to ''OFF''.

So, as I said a similar switch will be the simplest ''fix''. Or, a simple two-terminal switch can be used IF an ''idiot light'', diode, or resistor is used in the excite lead to limit current feedback from the excite terminal. A more complicated way of doing things, but an option if you don't want to continue things as they are.

I looked around this site and did NOT immediately find one for sale, you should be able to find a switch like yours at a nearby auto parts store IF there's a counterman with a little gray hair!

Or, GOOGLE ''Switch 3000-0961'', as an example.

This post was edited by wore out on 07/17/2022 at 10:38 pm.

Never seen a Farmall C with key switch. Been added , so Im not sure how they wired it and why . Three wires to key switch , trace out wire ing on paper , find out where it goes , get back with us post a photo of tracing .

White wire is from the amp gauge providing the power to the switch. Red wire is going to the alternator. Green wire is going to the ignition.