Technical 6 or 12 volt Headlight switch

I found this switch in a box of parts Made in USA, looks new to me. How do I tell if it is 6 or 12 volt? Bob

 

Does make any difference . 6 volt is really built to carry 2x the Amps as a 12 volt . Either way use it and enjoy

 

It looks like it has a rheostat for dimming the dash lights. That may or may not work well if it's the wrong voltage. But either way, it should work well enough to use it.

Does the circuit breaker (box at the back end of the switch) have a current rating stamped on it?

 

It has 20A stamped in ink over 253. I'm many years away from needing one, just want to list it properly. I'm clueless on electric stuff do all switches have circuit breakers? Will that stop the fire quicker than a fuse? Bob

 

Rotating the knob puts a ground on the dome light - not 12v. Door switches do the same. Door switch only has one wire. Opening the door grounds that wire. Dome lights are wired with 12V. The switch on the dome light also puts a ground to the lamp. That's why dome lights get two wires - one 12v permanently connected to bulb and one ground for the switch on the dome light.

 

The only real difference I've detected between 6V and 12V headlight switches are the rheostats that control dimming of the dash lights. The resistance values differ but generally they'll work with either switch on either system.

 

That looks exactly like the one I just bought of f of *bay.
It was for a 12 volt system.
KK