What is this???

I plugged my hard top wires in and plugged in a 4 pronged connector behind the 2nd rear windshield wiper below the speedometer. I flicked the switch up to a neutral position and then pushed the top half in all the way and everything electrical shut off until I released the switch. I also heard a grinding from the engine bay and my Rpms dropped to about 200. Btw nothing on the hard top works. Is this some kind of kill switch? The engine did not stall though