i have a 1993 ranger 4X4 with automatic 4X4 system. when i press the button for 4 wheel drive, the system does not engage. an audible click is heard in the 4x4 unit located behind the drivers seat, but no activity is heard down at the transfer case. there is a button on the 4X4 unit behind the seat; when it is pressed, a red light comes on. my question is, is this a problem at the level of the 4X4 unit or at the level of the transfer case, and how would i determine where the problem is. does anyone have any experience with this? thanks.