I have a 99 GMC Suburban with the push button four wheel drive system. I was driving the other day and noticed none of the lights on my four wheel drive selector were lit up. I changed out the 20 amp fuse for the transfer case. I can select 4WD Hi or Auto 4WD, when I try to select 2WD while sitting still the light for 2WD flashes for a few moments then stops. 4WD Hi remains lit up. When I try to select 2WD while the vehicle is moving I get the same flashing light on the 2WD button then the 20 amp fuse blows. When I install a new 20 amp fuse the 4WD Hi light is selected. While the fuse is blowed the truck "feels like" it is in 2WD, with a new fuse in the truck "feels like" it is in 4WD (I get a little wheel hop turning a tight corner on dry pavement). I have the new style plastic actuator on the front differential. Any ideas as to what this could be? Can the Auto 4WD really be working? (I live in wyoming and we can have snow at any moment. It would be nice if this feature continued to work properly while I try to figure this problem out.) Any help would be greatly appreciated. Thanks