Starter Solenoid
 

I bought one of these starter solenoids from BMI http://www.*************/12V-Starter-...d-_p_2279.html but can't figure out how to wire it. It has a single post for a wire but I can't figure out if it requires 12vs to energize it or should it be connected to a switch that grounds it to activate.

I emailed BMI and they told me they got those in a closeout deal and have no clue how they work.
Any Ideas?

yes lyon that small post would have to be energized by a 12 volt power source such as a wire that comes off your starter switch. the post you would hook it to, would be one that has power coming from it only in the start position. Once you turn loose of the key, it should not send any more power to it. One of the large post on the solenoid should be hooked straight to the battery and the other side goes to the large post on the starter. the battery side is usually marked as [bat].

Zman has it right. Think of those solenoids as a big relay, except the poles are exposed. A small current circuit controls a large current circuit. This allows smaller, lighter wiring from the start switch, and keeps the heat generated from the high current away form the passenger.

Once, in my younger years, installed high powered driving lights in a vehicle I owned, and without hesitation, bypassed the relay circuit and wired straight to the switch. The second time I used them, the switch melted and shorted the wires together, creating even more problems.

Attached is a diagram for the ford solenoid, disregard the 'I' terminal, as our buggies don't use it. FWIW, you might have picked one of these up at the parts store for about the same price and not payed BMI their weird shipping rates.