We have a unit here that has everyone stumped. Unit will not steer nor drive. Premium display shows SteerContact. The unit has (2) Curtis 1243C controllers and one 1310 MCU. The steer contactor ohm's out correctly and will close manually when disconnected from the system. All the wiring for the on-demand steering has been checked. The steer motor with the controller built in and the steer sensor has been replaced. None of the Curtis controllers shows a fault code when checked via a handset. If the positive wire to the traction contactor coil is unplugged, the steer motor goes into idle mode and operates correctly. Everyone here is thrown their hands up and we will not throw parts at it. Any help would be greatly appreciated.