i got 3, 1 On/Off/On, 1 Momentary On/Off, and 1 On/Off....
this is what they are for:
On/Off/On: in 1 on position, it will force the efan on no matter what, in the other on position it will be on auto function just like normal, and the off position, will be just that, off
Momentary On/Off: will be to change the flash pattern on my LED's in my grill (volunteer firefighter)
On/Off: will be the A/C compressor on/off switch...that way i can have it off in the winter time when the heat is on defrost....