I have two switches, one AC (3 wire, 3 position) & one Non AC (4 prong, 4 position) - the AC switch has had resistance issues in the past as the back has the typical scorched earth look to it - the 4 prong one looks fine. The question is can I use the non AC switch in the AC setup & will it still work, what is the 4th lead on that switch for & why does it have 4 positions instead of 3 - Off, L,M,H maybe??

see pic...

well I just answered one of my questions by looking at the controller face on the non AC version & it has an off position so the 4 position switch must be "Off -1-2-3".

The next question still is will it work in an AC controller - anyone know?
Thx!