The center Air vent is not working properly. The heater is not working. on 2003 Mercedes-Benz ML320

The A/C and Heater control head was not cooling, a used one was purchased and the A/C is now working but the HEATER is not. The dashBOARD center Vents(The Three FrontONES), not the Two left and Right vents are IS NOT WORKING. The A/C shop in my area says that I need to reprogram the system because His Scanner shows that all the motors are not working.What do you think?

Asked by for the 2003 Mercedes-Benz ML320