heyfolks i have a 2008 ford 250 gas crewcab truck that i purchased brand new,i have a problem that juststarted with damp and cool air coming to our province,my 4 x4 system will not engage when i use the shift on the fly switch when the hubs are locked into auto position but the 4 x4 ligt comes on.if i go and lock the hubs into the manual position and use the shift on the fly switch the 4 x 4 system activates,i was told if the auto position fails which i was told works on a vacume system you can lock the hubs in the manual system and it will activate the 4 x4 system.could it be a fuse or something more serious it works in manual hub position but not auto hub position