i just put my posi-lock in a couple of weeks ago. the cable goes thru the firewall down to the axle into the housing, when its unlocked its holding the fork towards the passenger side and pushing the button in, therefore cutting electric juice to the light in the dash. then when locked towards the driver side, the button is out making a electrical connection and the light goes on. im guessing its a backwards switch? i just plugged my 2 vac. lines because they go into a 4 line connecter on the tc. although i havnt tested it yet, havnt had a chance to go wheelin yet. but i checked it in the driveway before i tightened everything up.