After putting in 4x4 high to pull boat out of the water we hit the button to release 4x4 hi and it stayed in. After waiting awhile it would come out and will go into 4x4 low but not high. The axle is ingauging because you can feel the bind up in low range but not in hi. The lights flash for a few seconds but shuts off. Is there a test procedure for this. My scanner will not comunicate with the 4x4 system on this truck.