H Light Switch Wiring

I have a neighbor boy who is restoring an old H. He has her painted up and almost ready to go but can not figure out the lights. The switch is a 4 position switch that I am not familiar with. I have a 300 and I have seen other H models with a 3 position switch, off, dim, and bright. What is the other switch position and is there a wireing diagram that can help me out?

Chris

my SMTA only has a 2 position (from starting postion) switch which ive never seen either.

the following assumes a cutout relay, not a true voltage regulator. Jim

The positions on that switch are: 1) Lights Off, Regular Charge, 2) Lights Off, High Charge, 3) Dim Lights & 4) Bright Lights. I do believe the 4 position switch is indicative of a magneto. If no one posts a diagram, tonight, I'll scan my copy in the morning. - Mike

See if this diagram helps you.
4 Position switch with cutout relay.

<a href="http://s978.photobucket.com/albums/ae263/nemf/?action=view¤t=Picture005.jpg" target="_blank"></a>

The four position light switch can work just like the three position one. The 4th position ("L") controlled the cutout that was originally used in place of a voltage regulator.

IF your friend has a VR, he won't have anything connected to the "L" position.

Greg

Here is a diagram of the 3 position switch with a voltage regulator that you might want to keep for future use.

<a href="http://s978.photobucket.com/albums/ae263/nemf/?action=view&current=FarmallSchematicNew3-PosSwitch.jpg" target="_blank"></a>

Jeff Z,

I did not get either schematic, but it could be my provider.

thanks to everyone else for the help.

Chris

Sent you an email.

Spot on the with functions of the different position of the switch. Startin from fully to the left and moving clockise, L(ow) is a low charge rate, achieved by passing the current through the flat resistor at the bottom of an an original switch (not the modern replacement Jeff in the pictures acompanying Jeff Z's excelent schematic), H(igh) is a higher rate of charge, D(im) and the B(right) lights. The guts of the switch are such that they leave a high rate of charge when the lights are illuminated.

As for the magneto vs. 3/4 position switch, it is a coincidental relationship. A magneto is totally isolated from the rest of the tractor's electrical system. It will operate and spark your fuel reagardless of the light switch in use. THat doesn't mean yours is a bogus observation. It only happens that IH transitioned from magneto to battery ignitions over the same few years that they evolved from using cutout relays (4-position switch) to voltage regulators (3 position swithces). with the 4-position and a cutout, the operator served as the voltage regulator to control the charge rate by choosing a position on the switch. Tractors delivered with the 3-position switch, the regulator took over that function, so that the switch only determined whether your lights were off/dim/bright.