IHKA E36 Temperature Mixing

The temperature mixing flap is mechanically actuated, using the thumbwheel at the bottom left corner of the center face vent.

Fig 1: Identifying Temperature Mixing Flap

Any time that the face vents are open, rotating the thumbwheel will operate the mixing flap which is located above the space between the evaporator and the heater cores. Opening the mixing flap allows more cooled air to enter the face vent ductwork. Closing the flap increases the proportion of heated air which enters the face vent ductwork.

Fig 2: Temperature Mixing Flap Control Function