A/c function
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MBWorld Fanatic!
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E 350
A/c function
I have a simple question about the functioning of A/C unit. Does a/c and temperature controls function as one unit or independently. I mean I can turn a/c on and set the temperature to what I want; but if I turn a/c off I can still set the temperature???
Does a/c control cooling only or it controls both heating and cooling? Thanks.
Does a/c control cooling only or it controls both heating and cooling? Thanks.
Senior Member
Joined: Jul 2006
Posts: 268
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2011 E550, 2008 SL55 AMG
The temperature setting is independent of the A/C. That said, if the temperature you set is below the ambient temperature and the A/C is switched off, the system will not cool the car's interior to the set temperature.
You should also be aware that the A/Cs evaporator helps remove moisture from the air inside the cabin. With the A/C off, you might see a buildup of moisture on the inside of your windows.
You should also be aware that the A/Cs evaporator helps remove moisture from the air inside the cabin. With the A/C off, you might see a buildup of moisture on the inside of your windows.
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Joined: Nov 2009
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From: Southeastern USA
2010 E350 Luxury Sedan, Engine 272 (V6)
You need to go to MBUSA to ask this question. The M-B systems are very confusing and complicated and only MB (if even they) knows how they operate. What is off? On mine, I can push the OFF button and everything is off, but if I hit the temp button the HVAC system is engaged. This means both heat and A/C. A/C is always on if system is on, even in 210 degree cold weather when heat is on.
I can push OFF, then turn fan on, but this turns A/C on again. So I push A/C button and theoretically A/C is off. However, if it gets cold, the heat comes on. If I adjust temp, A/C comes back on.
Almost all cars sold today have a system where AC is always unless directly turned off, even when heat is on.
I can push OFF, then turn fan on, but this turns A/C on again. So I push A/C button and theoretically A/C is off. However, if it gets cold, the heat comes on. If I adjust temp, A/C comes back on.
Almost all cars sold today have a system where AC is always unless directly turned off, even when heat is on.
MBWorld Fanatic!
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From: NM
2023 AMG EQS
A/C stands for "Air Conditioning" if you think of it as the name implies then it is not cosmic at all.
That’s all it does, you either want the fan on with the air conditioned or you just want the fan blowing ambient or heated air.
It is not confusing or complicated no matter who makes it. lol
That’s all it does, you either want the fan on with the air conditioned or you just want the fan blowing ambient or heated air.
It is not confusing or complicated no matter who makes it. lol
Last edited by Tjdehya; May 14, 2014 at 01:39 PM.
MBWorld Fanatic!
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Posts: 2,616
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From: Southeastern USA
2010 E350 Luxury Sedan, Engine 272 (V6)
Actually is complicated
A/C stands for "Air Conditioning" if you think of it as the name implies then it is not cosmic at all.
That’s all it does, you either want the fan on with the air conditioned or you just want the fan blowing ambient or heated air.
It is not confusing or complicated no matter who makes it. lol
That’s all it does, you either want the fan on with the air conditioned or you just want the fan blowing ambient or heated air.
It is not confusing or complicated no matter who makes it. lol
However, in my 2010 E, there is NO vent only selection. Have to go through process I described above and even then, the computer will often take over to produce heat when it gets cold. BTW, there is NO heat button!
Had a Hyundai where if you turned off AUTO and then turned on AC and then turned AC off, you had a vent only function and could use the fan. System never overrode it. This was not in the manual.
For some reason, MB and some other companies want the compressor to be "on" at all times.
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Joined: Jul 2006
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2011 E550, 2008 SL55 AMG
Sounds like you're overthinking this. It's really simple - if the A/C is switched off, the A/C compressor will not engage and the HVAC system will provide only ambient air (i.e. vent). If the temperature is set higher than the ambient temperature the HVAC system will provide heat. Nothing complicated about that. Keep in mind that with the A/C switched off, the evaporator isn't working to remove excess moisture from the cabin so the inside of the windows may fog up.
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From: Calgary, Canada
'10 F150 FX4 SCrew. '14 S212S
I don't know why people don't just set the HVAC to a comfortable temp and let the computer do it's thing.
For me, when I pick up the car, I set my side to 21 and my wife's to 22 and the kid in the back to 23. Haven't touched them for 6000 kms (6 months) and it heats when it is cold inside the cabin and cools when it is too hot in the cabin.
Why pay and have auto HVAC controls when you constantly manipulate them? The car will blow hot air only when the coolant has reached the right temp. Running the fan on High and setting the temp to the Highest value will not heat the car faster. You are just likely to overshoot your desired temp and then have to cool the cabin because you are sweating.
For me, when I pick up the car, I set my side to 21 and my wife's to 22 and the kid in the back to 23. Haven't touched them for 6000 kms (6 months) and it heats when it is cold inside the cabin and cools when it is too hot in the cabin.
Why pay and have auto HVAC controls when you constantly manipulate them? The car will blow hot air only when the coolant has reached the right temp. Running the fan on High and setting the temp to the Highest value will not heat the car faster. You are just likely to overshoot your desired temp and then have to cool the cabin because you are sweating.
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MBWorld Fanatic!
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From: West Central Florida
2011 E550 P2 4M Sedan
In my experience, a car with an 'auto' setting where you set a desired temperature will always turn on the AC so it can achieve any desired temperature as quickly as possible.
The cars I've seen where you manually choose to turn the AC on or off are not automatic climate control. They have dials/adjustors for temp and fan speed and you decide when AC is needed or not.
The cars I've seen where you manually choose to turn the AC on or off are not automatic climate control. They have dials/adjustors for temp and fan speed and you decide when AC is needed or not.
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MBWorld Fanatic!
Joined: Oct 2010
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From: Southern US
2010 E550, 273 Engine: 2012 S550, 278 Engine
It can be very complicated depending upon how function was programmed. I have a 2011 Toyota and a 2005 Toyota. In those, I can turn on the fan and open the vents. If I want A/C, I push in the AC button.
However, in my 2010 E, there is NO vent only selection. Have to go through process I described above and even then, the computer will often take over to produce heat when it gets cold. BTW, there is NO heat button!
Had a Hyundai where if you turned off AUTO and then turned on AC and then turned AC off, you had a vent only function and could use the fan. System never overrode it. This was not in the manual.
For some reason, MB and some other companies want the compressor to be "on" at all times.
However, in my 2010 E, there is NO vent only selection. Have to go through process I described above and even then, the computer will often take over to produce heat when it gets cold. BTW, there is NO heat button!
Had a Hyundai where if you turned off AUTO and then turned on AC and then turned AC off, you had a vent only function and could use the fan. System never overrode it. This was not in the manual.
For some reason, MB and some other companies want the compressor to be "on" at all times.
I'm not sure what you are talking about.
In my car I keep it on AUTO basically at all times. But I have experienced with it. If I touch the MODE button the AUTO goes OFF. Then I can select where the air comes out with the MODE button and control the blower speed with the blower speed button. I can also hit the A/C button to turn the compressor OFF if I want to.
What in this is complicated?
Senior Member
Joined: Jul 2006
Posts: 268
Likes: 1
2011 E550, 2008 SL55 AMG
In my experience, a car with an 'auto' setting where you set a desired temperature will always turn on the AC so it can achieve any desired temperature as quickly as possible.
The cars I've seen where you manually choose to turn the AC on or off are not automatic climate control. They have dials/adjustors for temp and fan speed and you decide when AC is needed or not.
The cars I've seen where you manually choose to turn the AC on or off are not automatic climate control. They have dials/adjustors for temp and fan speed and you decide when AC is needed or not.
MBWorld Fanatic!
Joined: Aug 2009
Posts: 2,133
Likes: 265
From: NM
2023 AMG EQS
In my experience, a car with an 'auto' setting where you set a desired temperature will always turn on the AC so it can achieve any desired temperature as quickly as possible.
The cars I've seen where you manually choose to turn the AC on or off are not automatic climate control. They have dials/adjustors for temp and fan speed and you decide when AC is needed or not.
The cars I've seen where you manually choose to turn the AC on or off are not automatic climate control. They have dials/adjustors for temp and fan speed and you decide when AC is needed or not.
The automakers have not implemented a window fog detector system... Those lazy engineers!
You would think that such a technology isn't needed but after reading a couple posts in this thread it seems that we absolutely need this tech so that car air conditioning can finally become "complicated."
MBWorld Fanatic!
Joined: Mar 2014
Posts: 3,107
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From: West Central Florida
2011 E550 P2 4M Sedan
Hmmm... switching off the the A/C compressor does not mean the HVAC is not automatic. the system remains in auto mode and will continue to maintain the temperature set for each zone. It will NOT engage the A/C compressor if the temperature in a zone is above the temperature set for that zone. That's just the way it works. That doesn't mean it's not an automatic climate control system - it just means it's a smarter automatic climate control system.
MBWorld Fanatic!
Joined: Oct 2010
Posts: 5,142
Likes: 1,293
From: Southern US
2010 E550, 273 Engine: 2012 S550, 278 Engine
Incorrect! The AC is always on to prevent your windows from fogging up.
The automakers have not implemented a window fog detector system... Those lazy engineers!
You would think that such a technology isn't needed but after reading a couple posts in this thread it seems that we absolutely need this tech so that car air conditioning can finally become "complicated."
The automakers have not implemented a window fog detector system... Those lazy engineers!
You would think that such a technology isn't needed but after reading a couple posts in this thread it seems that we absolutely need this tech so that car air conditioning can finally become "complicated."
Defrost and AC MAX are the modes that keep the AC compressor running constantly.
MBWorld Fanatic!
Joined: Nov 2009
Posts: 2,616
Likes: 160
From: Southeastern USA
2010 E350 Luxury Sedan, Engine 272 (V6)
You have to Know
I'm not sure what you are talking about.
In my car I keep it on AUTO basically at all times. But I have experienced with it. If I touch the MODE button the AUTO goes OFF. Then I can select where the air comes out with the MODE button and control the blower speed with the blower speed button. I can also hit the A/C button to turn the compressor OFF if I want to.
What in this is complicated?
In my car I keep it on AUTO basically at all times. But I have experienced with it. If I touch the MODE button the AUTO goes OFF. Then I can select where the air comes out with the MODE button and control the blower speed with the blower speed button. I can also hit the A/C button to turn the compressor OFF if I want to.
What in this is complicated?
In mine, I have to push the OFF button, then push the MODE or FAN button, but this turns the AC back on. So I have to push the AC button to turn compressor off. Then I can use mode or fan as I want. However, the "heat" will come on if it gets cooler than the temp set on the "thermostat."
It would probably too complicated for the engineers to figure out, but it would be nice if there was a Vent Only button.
If you leave it in Auto, kind of doesn't make sense to put the windows down or fully open the sunroof.
Now, let's beat this dog some more!
