Warm light switch

I have 43 H with a magneto, generator, voltage regulator and 4 position switch. Tractor is 6 volt. The battery is not charging but the lights work and the ammeter shows discharge when the lights are on. If the tractor sits for a week or so the battery does not have sufficient charge to start the engine. The 4 position switch is warm to the touch whether the tractor is running or not. Could I have a short in the switch or instrument box or do I have a bad regulator that is drawing current to ground?

Sounds like a short somewhere. Switches aren't meant to get warm usually. Are the wires warm too?

Bad switch . I would be unhooking the battery until you get it fixed before you have a fire.

If the switch is warm that means there is current flowing through it, which explains why the battery is dead.

An H is pretty simple to rewire even without a harness, so I would recommend getting a new switch, some wire, and starting over. There are lots of good resources for simple wiring diagrams for those old Farmall tractors online. Yours should be the wiring diagram with the cutout, since it has a 4-position switch.

A 4 position light switch would be used with a cutout relay instead of a voltage regulator. With a cutout relay, the generator field terminal is connected to the light switch to control the generator output. With a voltage regulator, the field is controlled through the field terminal on the regulator. either way, the switch should not be warm.
I would first check for battery voltage on the armature terminal ("A") of the generator. With everything turned OFF, no voltage should be on the armature. Whether cutout relay or regulator, internal relay contacts connect the battery to the generator while running and disconnect when shut down. This would indicate the contacts are stuck.
Either way if you do have a voltage regulator, there is no reason for the switch to get warm. I suggest most like that wiring is at least part of the problem. The wire from the field terminal of the generator should go directly to the field terminal of the regulator only.
Basic regulator circuit would have power from the battery to the one terminal of the Amp-meter (usually a wire coming from the hot side of the starter switch). A wire from the other amp-meter terminal to the "BAT" terminal of the voltage regulator. A wire from the "GEN" terminal of the regulator to the "A" terminal of the generator. A wire from the "F" terminal of the regulator to the "F" terminal of the generator.
If you have a cutout relay, the "F" terminal of the generator connects to the appropriate terminal of the light switch. When the light switch is in the "H" position, the field is grounded for maximum generator output. In the "L" position a resistor is in the circuit which reduces the generator output.

When the switch is off, and the ignition is off, there should be nothing drawing current. The only thing that could draw current (if wired correctly) is a failing switch internal components. The light switch 1/2 of the compound switch has power to it from the amp meter. The generator control circuit should be disconnected from everything because it is not used with a real voltage regulator. A real voltage regulator is a composite device with a cutout relay and a field control relay inside. A cutout only looks the exact same externally (same cover and often with a field terminal that is fixed resistance, and used only when there are no lights on the tractor from the factory. So we need to know with certainty that you have a voltage regulator. If so disconnect any wire to the light switch generator connection. Jim

All helpful suggestions. I will work through them this weekend and get back to you with the results. Thank you.

Followed all of your suggestions, confirmed the wiring is correct and no voltage to the A terminal of the generator. Suspect a bad light switch, which I will repair (it does come apart) or replace with a new one. Thank you for the help.