AC button issue
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Newbie
Joined: Sep 2018
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E350 2012
AC button issue
I'm having a slight issue that I would appreciate some guidance on from the experts please. I have an E 350 MB. I turned the heating on in my car today, and noticed that the AC button was on, which I tried turning off by selecting it, but it won't shut off. I've cycled through setting temp on high and low and auto and this and that and every thing I can think of. Pls advise what to do? I don't know, is it an issue to run the heater when the AC light is on. I turned the temp from high to low to see if the AC is on and working and the air goes from hot to cool so that tells me the AC is on and working. Plus the display also tells me the AC is on. 
Member
Joined: Aug 2016
Posts: 130
Likes: 18
'11 E350 4Matic Sport
I'm having a slight issue that I would appreciate some guidance on from the experts please. I have an E 350 MB. I turned the heating on in my car today, and noticed that the AC button was on, which I tried turning off by selecting it, but it won't shut off. I've cycled through setting temp on high and low and auto and this and that and every thing I can think of. Pls advise what to do? I don't know, is it an issue to run the heater when the AC light is on. I turned the temp from high to low to see if the AC is on and working and the air goes from hot to cool so that tells me the AC is on and working. Plus the display also tells me the AC is on.
Thread Starter
Newbie
Joined: Sep 2018
Posts: 3
Likes: 0
E350 2012
AC Button Issue
Thanks for the reply. To answer your question. So got in the car at around 6 am, noticed it was a little cold inside, said ok let's turn the heating on, did that, and of course prior to turning the the AC was on from the day before, so I turned the temp settings on each side from low to high, and then saw that the AC button light remained on. I pressed it could tless numbers of times, and while the air from the vents got hotter, the AC button wouldn't turn off. And that is my issue. Have turned the car on and off left it off, come back to see if the AC button will turn off no matter what the temp settings are, but no success. The navigation panel confirms that the AC is on.
So no matter what I do I can't get the AC button to switch off. Somebody please advise.
Member
Joined: Aug 2018
Posts: 137
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2014 S550
The AC should stay on year round. It keeps the humidity down in the car and prevents fogging. As to your question, there are times when the system will run the AC compressor no matter how you have it set. Defrost is one of those times but there are more.
P.S. The AC compressor will NOT keep the heater from working as intended. Turning it off will not make the car get warmer faster.
P.S. The AC compressor will NOT keep the heater from working as intended. Turning it off will not make the car get warmer faster.
Member
Joined: Aug 2019
Posts: 85
Likes: 36
From: Birmingham, Alabama
'11 E350 4Matic Wagon
Wanted to bump this. I am actually having the same issue; if I hit the a/c button, it won't shut off. I don't really mind it being on, but figured that it could be manually cancelled outside of the auto mode. Any resolution to this? I have a 2011 E350 wagon/estate.
Newbie
Joined: Jul 2023
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MB E250 cdi
Did you ever find a resolution for this my 2014 MB E250 CDI is having the same issue the AC light is on Permanently and wont switch off.
Out Of Control!!
Joined: Apr 2019
Posts: 11,923
Likes: 6,776
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
Amazing AAC...
Your A/C can't be shut off...
That's a great problem to have in summer.
MB Aircon is software driven with help from a zillion comfort sensors. One of which is remotely located to sense windshield condensation.
You want to scan your car for faults and concentrate on the AAC Module issues.
That's a great problem to have in summer.
MB Aircon is software driven with help from a zillion comfort sensors. One of which is remotely located to sense windshield condensation.
You want to scan your car for faults and concentrate on the AAC Module issues.
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Member
Joined: Aug 2019
Posts: 85
Likes: 36
From: Birmingham, Alabama
'11 E350 4Matic Wagon
It actually was the control panel. I didn't try to take it apart to fix the button, although you could (you can buy buttons on Amazon, etc., which I had to do for my Saab key remote...you have to solder them on). Bought a new panel for about $140 and functionality is restored. Breakers/yards usually include the wood panel, too, and this one was better than the one I had on the original so that was nice!
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Out Of Control!!
Joined: Apr 2019
Posts: 11,923
Likes: 6,776
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
quick fix your AAC Module...
Sorry, I must have posted the question a few places, and forgot to answer here.
It actually was the control panel. I didn't try to take it apart to fix the button, although you could (you can buy buttons on Amazon, etc., which I had to do for my Saab key remote...you have to solder them on).
Bought a new panel for about $140 and functionality is restored. Brakers/yards usually include the wood panel, too, and this one was better than the one I had on the original so that was nice!
It actually was the control panel. I didn't try to take it apart to fix the button, although you could (you can buy buttons on Amazon, etc., which I had to do for my Saab key remote...you have to solder them on).
Bought a new panel for about $140 and functionality is restored. Brakers/yards usually include the wood panel, too, and this one was better than the one I had on the original so that was nice!
The way multiple people are experiencing the same "crazy A/C won't shut off" means it simply is not a random defect.
New pressed-pins work well before they get oxidized😄
If you are interested to fix this in 10mn for free... find the related solderless info here.
component-side showing clusters of opportunities
Reward your inner geek with a hardware encounter. Repairing your AAC Module is DIY friendly.
Last edited by CaliBenzDriver; Jul 27, 2023 at 04:20 PM.
Member
Joined: Aug 2019
Posts: 85
Likes: 36
From: Birmingham, Alabama
'11 E350 4Matic Wagon
The pictures are great. PC boards make me nervous. Took me a few days to build up the courage to solder back on a button on my Saab key remote! Not sure if solderless would be more or less scary.
Out Of Control!!
Joined: Apr 2019
Posts: 11,923
Likes: 6,776
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
go or no go ....
Circuit boards make me nervous too but that's because I know how they are designed with unnecessary narrow unprotected gaps...
Once you have clean GND connection AND reliable soldered pins then built-in chaos factors are disabled. More traveling with less troubles.
Last edited by CaliBenzDriver; Jul 27, 2023 at 04:17 PM.
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Joined: May 2021
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From: US
2008 E350, 2012 ML350, 2014 E350, 2015 ML350
. Reminder: perhaps practice on your car, but NEVER on your wife's,
