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Is the Auto AC smart enough to turn the AC off?

1566 Views 5 Replies 6 Participants Last post by  dagmando
I did my search, and I understand how the electronic AC works. However, I did not find the answer to this question.

Let's say we set the AC to auto, or even just turn it on. The AC seems to kick in. I understand it also works as a dehumidifier.

Since is winter, the Heat is running. There is no need for cold air.

Does that system smart enough to turn the AC off? Will it turn off once the humidity level is good?
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From what I've seen, it pretty much cycles the A/C constantly regardless. Doesn't mean it's producing cold air....but it's dehumidifying. I tend to just manually turn it off and on in the winter. Pretty much all new vehicles are doing this...I'm not a fan (pun intended).
The system is smart enough to turn the AC on. Dehumidification is needed more in the winter than the summer as people put out a lot of moisture. This mainly stops window fogging. It also extends the life of the compresser seals. By leaving it off all winter the shaft and seals expand and contract all winter. That was always a problem and all manufacturers advised to turn it on once in a while in the winter. It also keeps the bearings lubricated. The best thing you can do to increase the life of the AC is to leave it in auto. Mine stays on and the only thing I change is the temperature.
likely a dumb question, but...

would I be correct in understanding that the use of AC in auto mode year-round affects:

- wear on compressor/bearings
- tensioner/pulleys perhaps (or are they always running anyways)
- interior humidity
- engine load
- performance
- fuel economy (seems like a net 1-2 mpg)

Using AC itself does not affect the "charge" (level of refrigerant or ability to cool) unless you have a system leak.

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There are 2 sources of moisture causing fogging inside the car:
1. Outside humid air being sucked inside: usually when temp is above 32F. More moisture in Spring, Summer.
Below 32F, water vapor condenses and there is very little moisture in the air.

2. Human respiration: in such a small environment of the van cabin, if there are 7 passengers breathing, there will be some moisture produced.
- The car/van sucks air from inside, warms it and warm air enters cabin.
In all cars, there is a "discharge" duct hidden somewhere in the rear of the car so air can flow to the back of the car to outside.
- A trick to get rid of excessive moisture is to open the windows a bit (maybe 1-2 inches), this helps get rid of moisture.

In some vehicles, the outside temp sensor controls the AC too. For ex, if temp is below 25F or so, it shuts off the AC because at that temp of 25F, there is really no need for AC.

This "magic" temp (temp at which AC stops working) varies from vehicle to vehicle.
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would I be correct in understanding that the use of AC in auto mode year-round affects:

- wear on compressor/bearings

Quite the opposite, the worst thing for a compressor it not using it; it is designed to be used frequently to the oil keep recirculating.
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