Wiring Harness Colors

I plan on rewiring a 1953 TO-30 that has been converted to 12 volts. I plan on using the “Wiring Diagram for Ferguson TO-30, Continental gasoline engine w/generator (modified to 12 volt) from the FENA website. Do you know what the original color codes for the wires. The diagram is in black and white with no direction on what color the individual wires should be? February 5, 2016.

I’ve attached a wiring diagram that indicates the wire colors. The TO-30 diagram is the one at the bottom of the page.

You indicated you converted your 6 volt generator to 12 volts. When I convert these generators to 12 volts I change the field coils and the armature. I’m not sure your generator will have the correct 12 volt output unless you changed both the armature and the field coils.

When you convert from 6 volts to 12 volts you also need to change the ignition coil and the voltage regulator.

When you change the ignition coil to 12 volts you need to reverse the wires going to the coil. When converted to 12 volts, the negative (-) terminal on the ignition coil needs to be connected to the wire going to the terminal on the side of the distributor. The positive (+) coil terminal should be connected to the wire going to the ignition switch.

When installing the 12 volt battery, the negative (-) battery terminal should be connected to the ground strap, and the positive (+) battery terminal should be connected to the cable going to the starter switch. Remember to polarize the generator before you start the tractor. This was all covered in a recent issue of Ferguson Furrows. http://fergusontractors.org/nfs/wp-content/uploads/technical-articles/Polarizing-a-Generator.pdf

You may wish to consider purchasing a new wiring harness from Agri-Services. Agri-Services manufactures a very nice reproduction wiring harness that is an exact duplicate of the original. When you consider the quality and the cost to accurately reproduce these wiring harnesses you will understand why they are worth the price.

When you convert a TO-30 from 6 volts to 12 volts there is no change in the color of the wires using a 12 volt generator. The only change is in the components, generator, voltage regulator, and ignition coil but you must also reverse the polarity on the ignition coil wires and the battery cables. You can retain the original 6 volt starter as long as you only crank the starter for short periods of time. Cranking for long periods can burn up the starter. If that happens either have the starter rebuilt as a 12 volt or replace it with the 12 volt starter used on the TO-35 gas tractor.

Remember, these tractors work just fine with the original 6 volt system as long as all the components, starter, generator, voltage regulator, ignition coil, spark plugs, plug wires, distributor cap, rotor, points, condenser and fuel system are kept in good working order. Converting to 12 volts is no cure for failing to maintain these components. Starting problems are usually the result of undersize battery cables, a weak battery, a worn starter that needs rebuilding, or battery terminals that need cleaning or a tractor that needs a tune-up.