A/C turns on when I run heat
12-13-2016, 02:06 AM
#1
A/C turns on when I run heat
Why does the a/c turn on when I am only trying to run heat? I always have to turn off the a/c. No reason to have the compressor running when all Is heat. 2016 lt1 base.
12-13-2016, 02:50 AM
#3
It's for dehumidification. Helps prevent fogged windows and generally makes car more comfortable. Universally used throughout the industry when you choose "automatic" climate control.
12-13-2016, 07:41 AM
#4
Team Owner
12-13-2016, 08:04 AM
#5
Do you have it on the "auto" setting?
A/C light will always be on in that setting, but that doesn't mean the compressor is running. In all modern vehicles, the compressor only runs when the system call for a cooler temp.
A/C light will always be on in that setting, but that doesn't mean the compressor is running. In all modern vehicles, the compressor only runs when the system call for a cooler temp.
12-13-2016, 08:11 AM
#6
Team Owner
"Press AUTO to return to automatic operation and the air conditioner runs as needed. When the indicator light is on, the air conditioner runs automatically to cool the air inside the vehicle or to dry the air as needed to defog the windshield faster"
Last edited by JoesC5; 12-13-2016 at 08:17 AM.
12-13-2016, 09:05 AM
#8
Duplicate of below
Last edited by Foosh; 12-13-2016 at 09:19 AM.
12-13-2016, 09:06 AM
#9
Safety Car
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That is wrong....the compressor runs if you use the defroster or if you call for HEAT and keep the A/C on. The only way the A/C Compressor doesn't run is if you turn it off for cooling or heat. It will ALWAYS go on for defrosting.
12-13-2016, 09:06 AM
#10
Le Mans Master
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It's quite proper to run the ac year around anyway. It is a component that will thrive longer.
12-13-2016, 09:09 AM
#11
Wrong answer. You should read post # 2 & #3 for the correct answer. Or you can read your owners manual.
"Press AUTO to return to automatic operation and the air conditioner runs as needed. When the indicator light is on, the air conditioner runs automatically to cool the air inside the vehicle or to dry the air as needed to defog the windshield faster"
"Press AUTO to return to automatic operation and the air conditioner runs as needed. When the indicator light is on, the air conditioner runs automatically to cool the air inside the vehicle or to dry the air as needed to defog the windshield faster"
That's what I said. Yes, I neglected to add "dehumidify," but the operative point was just because the light is on does not mean the compressor is running. It runs as needed to either cool or dehumidify.
Last edited by Foosh; 12-13-2016 at 09:30 AM.
12-13-2016, 09:15 AM
#12
Another example, two of our other cars have engine start/stop. If the engine is shut down at a stop, and the system calls for cooling while the engine is shut-down, the engine will restart to run the compressor.
All modern cars operate the same way for fuel economy reasons, as the AC compressor has a clutch system which allows the pulley to "free-wheel" when it has no need to run.
Last edited by Foosh; 12-13-2016 at 09:26 AM.
12-13-2016, 09:52 AM
#13
Team Owner
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Sorry OBX, you're apparently not understanding either. The compressor turns on and off even when cooling. If you cool the interior to 66ºF in the summer, and that get's too cold, and you turn it up to 72ºF, the compressor will shut down until it reaches the temp you've selected, then it will run, as needed, to maintain that temp.
Another example, two of our other cars have engine start/stop. If the engine is shut down at a stop, and the system calls for cooling while the engine is shut-down, the engine will restart to run the compressor.
All modern cars operate the same way for fuel economy reasons, as the AC compressor has a clutch system which allows the pulley to "free-wheel" when it has no need to run.
Another example, two of our other cars have engine start/stop. If the engine is shut down at a stop, and the system calls for cooling while the engine is shut-down, the engine will restart to run the compressor.
All modern cars operate the same way for fuel economy reasons, as the AC compressor has a clutch system which allows the pulley to "free-wheel" when it has no need to run.
Wifey's BMW does this also.
12-13-2016, 10:03 AM
#14
Tech Contributor
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I had a hang on air conditioner added to my 65 Olds 442 after moving South in 66. That unit only had a temperature and fan control but would keep on running even though the evaporator temperature was below 32 degrees. It would constantly freeze over in high humidity conditions. Nothing like having an AC unit start throwing ice particles in your face when you are driving down the highway. Traded that for a 68 Olds with factory air which controlled the system so the evaporator wouldn't freeze over. However, the OM said to run the AC at least once per month to keep the compressor from going bad.
Bill
12-13-2016, 10:33 AM
#15
Team Owner
Joe, no my answer was a right answer and you're full of it. You may read your manual, but you apparently have some trouble comprehending what "automatic" and "as needed" means.
That's what I said. Yes, I neglected to add "dehumidify," but the operative point was just because the light is on does not mean the compressor is running. It runs as needed to either cool or dehumidify.
That's what I said. Yes, I neglected to add "dehumidify," but the operative point was just because the light is on does not mean the compressor is running. It runs as needed to either cool or dehumidify.
Modern systems(for decades) have used a variable displacement compressor where the pistons stokes are changed depending on load.
The external clutch is only used to completely shut off the A/C system or when it's necessary to automatically protect the system's components.
The Compressor/system runs all the time and the displacement of the compressors varies to meet the conditions expected of it. if you don't want the system to run, then you manually shut the system down by using the hard button on the control panel to use the external clutch to disengage the compressor from the drive pulley.
In the Auto mode, no matter if you are cooling the interior or heating the interior, the compressor runs all the time.
http://delphi.com/docs/default-sourc...f.pdf?sfvrsn=0
Last edited by JoesC5; 12-13-2016 at 10:37 AM.
12-13-2016, 10:37 AM
#16
Instructor
As many have stated, A/C light on means compressor may engage if required. Most systems today are CCOT so the compressor cycles to maintain the evaporator around 34 F to prevent freeze up of the evaporator. If ambient temperature is low enough, the A/C clutch will not engage even if A/C light is on.
12-13-2016, 10:45 AM
#18
Team Owner
Joe, no my answer was a right answer and you're full of it. You may read your manual, but you apparently have some trouble comprehending what "automatic" and "as needed" means.
That's what I said. Yes, I neglected to add "dehumidify," but the operative point was just because the light is on does not mean the compressor is running. It runs as needed to either cool or dehumidify.
That's what I said. Yes, I neglected to add "dehumidify," but the operative point was just because the light is on does not mean the compressor is running. It runs as needed to either cool or dehumidify.
Now you are trying to back track your answer with your 'edit' to cover up your lack of understanding of automotive A/C systems.
12-13-2016, 10:48 AM
#19
Team Owner
As many have stated, A/C light on means compressor may engage if required. Most systems today are CCOT so the compressor cycles to maintain the evaporator around 34 F to prevent freeze up of the evaporator. If ambient temperature is low enough, the A/C clutch will not engage even if A/C light is on.
12-13-2016, 11:57 AM
#20
The bottom line is the compressor is not always "running" because it's output can vary from zero to full capacity, regardless of what technology they use to accomplish that. The mechanics are irrelevant to this discussion. Moreover, using the term "cool" also covers "dehumidifying" since it's the cooling process that removes humidity from the cabin air. All the compressor does is cool, it doesn't have a dehumidifier in it, per se. Every AC system is a dehumidifier by definition.
I ignore your posts, and do not respond to any of yours except when you attack. I have no interest in anything you have to say because of your tone and attitude. Please do the same.
Last edited by Foosh; 12-13-2016 at 12:14 PM.