I looked up in books related to electronics to find out about Pulse width modulation(PWM).
KiaMech you claim that there will be possible rise in the temperature of the solenoid inside the BorgWarner transfer case.
OK I agree that thr microprocessor in the TOD unit is designed to send digital signals based on duty cycle.
For the case of Sorento TCCM unit transfer a variable percentage of engine torque to the front axle (0% to 50%) by means of a PWM (Pulse Widht Modulation) of 50Hhz (cycles per second), with a maximum duty cycle of 88%.
So it was easier for them to use PWM because they can take the signals from front and rear shaft sensors located in the transfer case and feed the TOD unit.The output has a frequency modulation of 50 Hz,with 88% of 13.6 v of battery,that is 12v when "locking the central differential".
If you read here
http://www2.clubterracan.net/problema_tod_...acan%20Full.htm
these people made experiment and discovered that after 1 hour of using 12v the rise of the temperature in solenoid was not significant at all.
I think there is no risk at all and that is why KIA and HYUNDAI of Spain accepted the fault and constructed a similar blockade.
Besides BorgWarner claim that their transfer case has this possibility but it was decision of KIA to program the microprocessor in this way.
I am waiting for your opinions
thank you