AC blower fan turns down when putting car in reverse?
 

Hi all,

I have a question and have not seen it addressed in the manual.

When I put my car in reverse and back out of a parking spot, is it normal for my AC fan to turn on low? When I put it in drive it is at full speed again. It does not happen everytime but anyway I want to know if it is normal or a problem with my car.

Sounds odd. I notice sometimes my a/c fan fluctuates a little in speed at its leisure...never bothered to get it looked at.

Mine does the same, when on automatic mode. Reverse it slows down and once in drive it goes back up.

stab in the dark guess -- but I bet its so that you can hear the reverse parktronic beeping sounds better if you had that option... but even though we don't - it does it anyway... Or maybe to hear the kid screaming that your about to run over? ;-)

- Eric

My guess is that they had both in mind when they put that feature in our cars (yes, mine does it too), but they'll only admit making it easier for the driver to hear the parktronic beeping.

Mine does it too.

these pics are from the screen showing the malfunction... Anyone happen to know what could be the problem or how to fix it???

mine does it

This has been standard in many European cars, like my ex Audi A4 for years. It's meant to prevent the exhaust fumes to be sucked into the car while reversing. It's actually explained in the car's manual, atleast in the Audi. Haven't received my MB yet, so can't comment on the MB manual yet.

In the A4 the AC also turned down when using the windshield washer. Again to prevent the fumes to be sucked in.

Never noticed that will have to keep it in mind. To the OP with those screen shots I would have it looked at during the next service.

External fan?
 

The only external fan is the one behind the radiator, not the fan in the heating system. And, that could be a stored code from some past event.