Sometimes when it gets really cold outside circulating the air from inside of a car helps to quickly warm the interior. I do that all the time in my Korean made Daewoo. However, my MB climate control system has 2 temperature wheel controls, a fan speed and air direction switch. The very end position of the fan switch seems to lock the air but also stop the fan. How can I lock the outside air and circulate the inside air to quickly warm the interior?
Thanks

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1989 230E, 8v, 166.000 km, updated to 94/95 trunk & hood
2002 Daewoo Nexia 50.000 km
Sold:
1987 VW Jetta GLE 16V, Recaro seats
1982 Volvo 240 DL (lovely car!)
and few more american cars.