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      11-19-2012, 07:04 AM   #27
Major General

Drives: BMW F11 535i Touring
Join Date: Mar 2007
Location: Scotland, Highland Region

iTrader: (0)

Originally Posted by parapaul View Post
AFAIK there is only one cabin temperature sensor, which is in the middle of the console - so I genuinely don't know how it can try to keep 2 temperatures.
BMW Data:

The temperature inside the vehicle is controlled by means of a master controller.

Control is based on the nominal values set and the calculated actual value (the nominal values are set with 2 temperature selector knobs. The actual value is calculated from the temperatures measured by the interior temperature sensor and the footwell temperature sensor).

The lead parameter is calculated from the comparison between the actual value for the interior temperature and the corrected nominal value (calculated from temperature request, interior temperature and ambient temperature). Compared to the set specification, the interior temperature is raised in the cold so that a comfortable level is achieved even at negative temperatures, despite the temperature setting being unchanged.

The ambient temperature is transmitted to the IHKA control unit via the K-CAN.

The separate temperature setting for the driver's side and the front-passenger side makes 2 mixer flaps necessary.
So it appears to use the two temperature requests, two sensors and corrected values. Adjusting via the two (sided) mixer flaps.