thanks for the answer. let me clarify just a little, after reading i think it might help. maybe you have already answered it. Back in the day I had a ford pickup that had a little lever thit i slid back and forth that would make either cold or hot air blow and it would change immediately. In the mercedes, if i change the temperature from lets say 60 degrees to 80 degrees, it will continue to blow cold air for about 5 minutes, then it will slowly start to change to warmer air. it still continues to blow cold air the entire time. the same is true if i would switch from 80 to 60 degrees. hope that helps clarify. i know sometimes it is hard to put this stuff to words!

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1994 C280
2009 VW Tiguan
1993 Toyota X-tra Cab SE-5


1973 220D ... Gone, but not forgotten
1991 Alfa Romeo 164L Gone, wife MADE me forget it

2006 Hyundai Tucson... just straight out FORGOTTEN!