thank you for posting this.
Today I found myself with the exact same problem as OP, tho I swear I was able to turn on the MAX A/C button before when outside temps were below 0° C and I enter an underground car park and the heat/moisture totally fog up my windows... even my beautiful gold colored, aspherical passenger mirror does not auto defrost now These gold colored mirrors are hard to find. I dont want to switch to the blue ones...

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I swear, my cars are like a girlfriend.
Sometimes its a rough ride, sometimes its smooth motorin'.
Sometimes she doesnt like how i treat her and sometimes i dont like how she behaves.
BUT at the end of the day, she loves it when I am inside her.

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'91 850i
'05 X5 4.4i
'09 Clubman S