Hello, my car doesn't have this?

[Chapap]

Wait, what? Those "close door" buttons don't work. I have been wasting energy pushing that damn thing this whole time. FML

LOL only sometimes… and crosswalk buttons

 

[sgtsandman]

what happens on cars that have both a recirc and max setting? Is it just redundancy?

I can’t speak for all makes. Of the the more modern vehicles that I’ve had that had a separate recirculation button, it was completely independent from the A/C and the heat. It gives you the option to select it whenever you want.

The 2019 Ranger, going to max A/C operates the recirculation automatically but in the other settings, you have to select it yourself.

Redundant but not at the same time. There are times when being able to select it when you want is beneficial. As to when that is, is an individual decision. Sometimes when heating or cooling, it helps maintain temperature better but there are times, like in high humidity, when it can cause the windows to fog up if you aren’t in A/C mode to dry the air.

 

[Chapap]

… like in high humidity, when it can cause the windows to fog up if you aren’t in A/C mode to dry the air.

Are you talking about turning the compressor on and off? That would cause high humidity, but Max AC indicates something different is happening when you press it. Perhaps some cars have variable pressure refrigerant systems?

 

[sgtsandman]

Are you talking about turning the compressor on and off? That would cause high humidity, but Max AC indicates something different is happening when you press it. Perhaps some cars have variable pressure refrigerant systems?

Not that I’ve seen. Because the evaporator gets so cold, it draws the moisture out of the air. That’s why manufactures often have the A/C come on when you select defrost.

MAX A/C goes to recirculation so it can cool the air in the cabin off quicker since the system is just cooling the air more each time is runs back through instead of constantly cooling air drawn in from the outside.

The same thing can be done when heating the air but one has to watch since there is no air drying going on by the evaporator of the A/C system.

 

[kr.ppoo]

thank you all

Does the air conditioner compressor have to run?

I just want to block the outside air

I'm using a translator, so I may not understand

 

[superj]

i guess if your compressor is broken than no. but i bet it comes on when you hit max ac

 

[RonD]

Yes, AC compressor should run, especially in winter months
As said it DRYS the air, pulls out moisture

In winter, shoes and clothes are often wet or damp from rain or snow
So YOU bring in alot of moisture when you get in to the vehicle
YOU also exhale alot of moisture, lol, as do all passengers inside the vehicle

With AC on all the time the air inside the vehicle gets dehumidified(dried), this prevents fogged windows but also any musty smells that WILL develop over time with damp interiors

If you are concerned with MPG then you can unplug the compressor, or pull out the AC relay when you don't want it to be on
Users choice
But I would activate it once a month for a day or two to keep system in good shape, i.e. lubed