Three position light switch with resistor

[46chief]

I am restoring a LA John and I can understand the high and low function of the light switch but if a tractor only has two lights what is the third position on the switch for? Thanks

 

[PopinJohn]

Off.

 

[leon]

Likely manual control of the generator's charge rate.

 

[buckeye al]

Actually the high & low is NOT for the lights! It is the generator's charge rate!

The switch has three positions and controls two things, the generator charge rate & the lights. HOWEVER.... with that system the lights are either on or off. There is no high and low or bright & dim, just on or off! The three positions of the switch provide:

-when all the way in, the lights are off and and generator is in the LOW charge mode.

-With it pulled out to the first detent (maybe only 1/4" out) is high generator charge rate & lights are still off. This is for quickly re-charging the battery from a start if the engine will only be run a short time as if you''re just moving it outta the way to get to something else it had parked in.

-With it all the way out, the lights are on & the generator is in the high charge mode.

The switch has a thin brass tab which the mounting stud goes through. This tab has to butt up against a good ground or the generator will not work! The switch has three wires attached to it. One is the battery feed IN to the switch for the lights. Another is out to the lights. These two are in line with each other (on original switches) along one side of the switch. The third wire connects with the F post of the generator and mounts to the switch's resistor. It is on the opposite side of the switch's board from the light and battery terminals. This unit is actually two switches configured side by side into one unit.

Hope that's helpful.

 

[46chief]

Thanks buckeye, that helps a bunch.