AC fan speed stronger when top up vs. down
Thread Starter
Junior Member
Joined: May 2019
Posts: 15
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2018 E400 Cabriolet
AC fan speed stronger when top up vs. down
When my A/C is set on auto with the top down, and then I raise the top, the fan speed of the a/c increases considerably. It would make more sense (to me) for the a/c fan speed, if it was different with the top up vs. down, to be higher with the top down than up. I want/need more cool air when the top is down and there's no shade, compared to when the top is up.
My dealer states that this operation is "normal operation", that "the blower motor of the a/c will never be able to overcome the outside temperature, therefore the a/c system reduces the blower speed to increase efficiency of the overall vehicle."
Can anyone confirm that this is in fact normal operation? My convertible audi was the exact opposite, higher fan speed with the top down.
Thanks!
My dealer states that this operation is "normal operation", that "the blower motor of the a/c will never be able to overcome the outside temperature, therefore the a/c system reduces the blower speed to increase efficiency of the overall vehicle."
Can anyone confirm that this is in fact normal operation? My convertible audi was the exact opposite, higher fan speed with the top down.
Thanks!
Member
Joined: Jan 2014
Posts: 101
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From: Springville, UT
2015 S550 ordered
I’ve been noticing this as well but I like the way it works. My last convertible was an Audi S5 and I was living in Texas so I like the A/C blasting if I was going to drive top down on the hottest days. (I usually just left the top up which defeated the purpose.) But now I’m in Utah where top down weather is great. So having the fan go down when I lowered the top is just fine. Mostly I just turn the climate control off when I’m driving top down here.
But answer your question - my E53 operates the same as yours.
But answer your question - my E53 operates the same as yours.
Last edited by DFW_Neal; Jun 3, 2019 at 11:22 AM.
Super Member
Joined: Nov 2017
Posts: 669
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From: Hermosa Beach, California
2018 E400 Coupe
I suspect that the fan has to work harder to move the same amount of air when the roof is raised (and windows closed) as opposed to when it's down. Simple physics — when the roof is up, the fan is blowing into an enclosed space, which requires more effort (energy) than when it blows into an unenclosed space. It's a bit like the difference between blowing up a balloon and just blowing hot air.
Thread Starter
Junior Member
Joined: May 2019
Posts: 15
Likes: 1
2018 E400 Cabriolet
I suspect that the fan has to work harder to move the same amount of air when the roof is raised (and windows closed) as opposed to when it's down. Simple physics — when the roof is up, the fan is blowing into an enclosed space, which requires more effort (energy) than when it blows into an unenclosed space. It's a bit like the difference between blowing up a balloon and just blowing hot air.
On Audis, the opposite is true, the fan speed of the a/c increases when putting the top down. Audi engineers have apparently actually been in a convertible, and note that it is often hotter with the top down, and thus chose to increase the fan speed to provide additional cool air when it's needed most.
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