the Tow/Haul system in my 2002 tahoe has stopped working completely.a week ago it would only change fr4om the on or off position when the vehicle was in park but now it does not work at all, the light does not even turn on. i have been told by one person that it could just be that the actual momentary switch itself has gone bad and that its an actual actuato on the transmissio that needs to be fixed by another guy. ANyone know anything about this or how to fix it?