SL/R230: 2005 SL 500 Top down A/C question
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Newbie
Joined: Jun 2018
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SL 500
2005 SL 500 Top down A/C question
I just picked up a 2005 SL 500 in really nice shape with about 46K miles. The car is awesome and I discovered something yesterday that has me a bit confused. When I have the AC cranking away and blowing pretty hard, Auto setting or manual, and take the top down, the blower slows down. When the top goes back up, the blower goes full force again. Is this designed that way or do I have an issue? It would seem that with the top down, you should be able to get the maximum cooling and fan power but hey, what do I know other than it seems like a great vehicle so far.
Junior Member
Joined: Aug 2016
Posts: 18
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From: Bremerton, WA
2005 SL500 Designo Edition
My 2005 does the same thing and I remember reading somewhere that it is normal. Appearantly the MB Engineers felt that if it was nice enough for the top to be down, you don't need the climate control working full on. You will also notice the audio system changes from when the top is up to when it is down.
Junior Member
Joined: Jun 2018
Posts: 18
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2009 SL550R
Ya, just picked up a nice 09 yesterday. Same thing...odd AC operation. But it will take a while to figure it all out.
Mine has these 3 dials on the dash between the center vents that seem to direct air one side or the other...but that's another oddity...still trying to figure out how those operate.
Mine has these 3 dials on the dash between the center vents that seem to direct air one side or the other...but that's another oddity...still trying to figure out how those operate.
Senior Member
Joined: Jul 2015
Posts: 355
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From: amarillo texas
2003 sl 500
dash vents
The dial wheels open or close the 4 dash vents. The left and right wheels open or close the appropriate end vent and the middle wheel opens or close the two center vents. I rarely use them as my auto temp system will regulate them as needed. Even more interesting is if you push on the "auto" button (on the two temperature wheels) the plunger pops out showing a myriad of other possible combinations of ventilation options. See your manual about these combos. Again, I rarely use that feature as "auto" at least for me, does a very good job of temp control. Pushing "auto" on the blower button will cause it to pop out and you can manually control blower speed, that is quite useful.
moretech
moretech
Junior Member
Joined: Jun 2018
Posts: 18
Likes: 1
2009 SL550R
The dial wheels open or close the 4 dash vents. The left and right wheels open or close the appropriate end vent and the middle wheel opens or close the two center vents. I rarely use them as my auto temp system will regulate them as needed. Even more interesting is if you push on the "auto" button (on the two temperature wheels) the plunger pops out showing a myriad of other possible combinations of ventilation options. See your manual about these combos. Again, I rarely use that feature as "auto" at least for me, does a very good job of temp control. Pushing "auto" on the blower button will cause it to pop out and you can manually control blower speed, that is quite useful.
moretech
moretech
MBworld Guru
Joined: Dec 2009
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NO LONGER ACTIVE
There are a couple of things going on. Yes, the engineers figured you don't need the AC in max mode if you are going to ride with the top down. The other thing is that the ACC's decision to kick into high-speed max mode is based both on temperature and cabin humidity. There is a sensor located in the overhead control panel. When you open the top, it ignores the humidity sensor, and that will also affect how forcefully the air blows.
