any ideas what this is ?

just removed the tow hitch/electrics from my G . unplugged the 2 merc secrew in hitch electric sockets. there is a third that is wired into the main loom and looks factory fit AND a forth, but this is a four pin socket , on opening it up only two are wired in with very heavy duty cable (earth/live) it is marked 10/15 amp 380v ????? in the engine bay , under the filter box (mounted to inner wing) there is what can be descibed as a 'coil' ( petrol ignition type) that has huge wires straight from alternatot (invertor?) in glove box there is dyno tape for unladen/laden tyre pressures - just like military/fleet/company vehicles tend to have! any ideas? im guessing ex utility maybe?