I have a 95 GMC surburan 2 WD we were driving to Las Vegas yesterday and on the highway it just died. We pulled to the side of the road and it would not start. (not even crank) Completely dead. It is at a shop in Kingman AZ and they dont know what it is. has a new battery, we checked the Alt. & starter. There is no power to the fuel pump or to the gauges. What else might it be??