I installed a NOS ignition switch in my 52 1/2 ton about 2 weeks ago. It was not marked either, so I just tested all 3 terminals with my VOM. With the key in the off position all three terminals are insulated or open. With the key in the on postion all 3 terminals are closed or conducting. Pick any terminal for the BAT connection, then the other 2 will get voltage when you turn the key. I finished all my wiring last weekend and it works great.
shoeless
