Part 2 is complete! I have a good idea of the sensor circuit characteristics in the xDrive actuator now and can start designing a system. About 42% of the way there, but can start making a schematic for the controller hardware and play with some software.
AWD E36 Project xti: Reverse Engineering xDrive Actuator Circuits|ATC300 Transfer Case Sensors Pt 2
Next up we will be putting the actuator back together and mounting back to the transfer case to characterize the system as a whole.