go to put the truck in 4 high and it engages, climb on out of the mud, shift back into 2 hi and the light doesn't go out. stop, then back up(usually that works) and nothing. shift back into 4 hi and the light goes out. back into 2hi and the light comes back on. pull off to the side of the road and dump it so i know it's only in 2hi, because the only the back spins. are my hubs still locked for my light to be on or os there a sensor that controls the light that could be bad?