TO-20 Wiring Diagram

I am looking for a wiring diagram for my 1949 TO-20, I have to rewire it.

You can find a copy of the original wiring diagram on your FENA web site.

A 1949 TO-20 would be a TO-20. These were originally equipped with a discharge warning light and no ammeter but Ferguson supplied instructions to install an ammeter if the customer wanted one. Wiring diagrams for a TO-20 with the original warning light, and one with an ammeter are available on our website.

There is also a wiring diagram to install a Delco alternator though I suggest you retain the original 6 volt positive ground electrical system. Some people seem to think converting to 12 volts improves starting but often the problem is their starter needs rebuilding or repair or the battery cables are undersize. Clean terminals, cables of the correct gauge and a good ground connection are more important with 6 volt systems.

The starters on these tractors are small but when kept in good working order will work just fine. If you do convert to a 12 volts, alternator or generator, you will have to install a 12 volt coil, wired with the primary side (+) positive terminal connected to the ignition switch. With the 6 volt positive ground system, the primary side (-) negative terminal is connected to the ignition switch. If you are careful you can use the original 6 volt starter as long as you don’t crank it for long periods of time and cause it to overheat.

You will find other wiring diagrams and other resources on our website.