I put the truck up on 4 jack stands and found that the 4x4 was not working in LOW and HIGH.
So i found the front VSV's . each have a line that goes to the axle. and they both are pulling vacuum with the switch on or off .
If i leave hose #1 on and remove hose #2 , with the auto button on, it seems to be working normal . when i press the off button, i have to reconnect hose #2, and remove hose #1 to disengage the axle .
Because of this i guess both VSV's are stuck open and pulling vacuum . would this be safe to say ? Dealer wants $250 for the pair of switches . A-lot of money on a guess.