I have a 1998 GMC Jimmy. It does not seem to want to shift into 4x4 (electronic shift). The problem seems intermitten. I just purchased the vehicle.When I shift to 4x4, the 4x4 lights flash, then it kicks back to 2 wheel drive. It is -6 out and the windchill is probably -30. Could the cold weather be affecting the shifting? Will it correct itself during warm weather?