Outer Limits 4x4 Board

My SWB MQ does not put its reverse lights on. the wiring is ok (because if i unplug the wires from the switch and put them together then the the lights go on). its is 100% without a doubt the switch that is stuffed.

anyone know what could be wrong with it? is it possible to replace it with the gearbox still in the car (i dont want to pull it apart). i tried twisting the black plastic (thinking it was a unit) but that just ripped off exposing a sort of foam and some more wire. there is a large (~22mm) bolt as well. if i take this off, is that the switch and i can just put a new one on? will oil piss out of the gearbox?

cheers.

Oil shouldnt come out. Pretty sure it is above the filler.

My reverse lights didnt work however it was a dodgy connection in the plugs (someone had added spade terminals and these had come loose)

You should be able to test the switch with a multimeter b4 you pull it out too.