Wasn't sure if the driver still needs to manually toggle this on or off. I haven't seen it toggle on the ac yet.

 

What does "toggle AC" mean?

 

Good question. I was wondering the same thing.

 

If you turn the automatic climate control on, the default is to have the A/C compressor on all the time, unless you turn it off. Whether it actually cools or not will depend on temp settings.

 

Enable or disable the ac button/mode.

 

I don't think that just because the A/C light is on, the compressor is on. I can't imagine Nissan would allow the compressor to compress in cold weather and the car still get 30mpg.

 

I hope you're correct, because I leave that button "on" all of the time and just adjust the temperature. I figured that was the way it was supposed to work. If you're supposed to turn it off when using heat, how would anyone know what the magic temperature was at which you're supposed to turn off the A/C button? If anyone has a different idea on this, please speak up.

 

Pulled this from a different site.


Climate Control

Think of this as ‘smart air con’. Climate control still cools the air in summer, but does so intelligently. You set a specific temperature on the dial (say, 72 degrees) and a computer uses sensors to vary air con output to maintain this.

No matter if it is +90 degrees or -10 degrees outside, the interior of your car will always be kept at the temperature you set. It does this by smartly blending cold and warm air, constantly adjusting the balance to maintain an interior climate.

It’s real ‘set and forget’ stuff – some owners say they set the temperature once, when they had the car new, and haven’t touched it again in all the time they've owned it.

Climate control also often offers ‘dual zone’ control: the passenger can set a different temperature zone to the driver. Really expensive cars have multi-zone control, so those in the back can create their own temperature cocoon too.

For this reason, climate control is more expensive than standard air con. It requires sensors, digital displays and complicated algorithms to juggle fan speed, temperature flow and air con usage.

There is an added benefit to climate control though – it has the potential to save you money. Because it only uses the air con when needed, it may consume less power than standard ‘dumb’ air con which simply runs unchecked all the time.

Some modern climate control systems also have an ‘economy’ setting that do all the climate-controlling work without using the air con system (or using it only minimally). The car won’t be as cold in summer but you probably won’t notice when it’s colder – and you’ll save a lot more fuel as you go, too.

Needless to say, if you buy climate control, you’re also buying an air con system. Just a much more intelligent one…

 

Well put Richard66. The A/C will not operate once the ambient temperature switch detects temps in the freezing range regardless of the engagement switch position. Climate control does utilize the A/C in even the defrost mode to dehumidify the air depending once again on the outside temps. I like the "set and forget" analogy.

 

Richard66,
Thank you for all of the information. Most of this was already clear to me, but there is one thing that I have never truly understood and it all revolves around the "A/C" button. My Mercedes was the same as this Maxima as far as the controls go. With both vehicles, I have always just selected "auto", set the temperature, and pretty much left it alone unless I needed to change the temp or the mode. If everything is automatic, why are you able to turn the A/C button off? It seems that it stays lit all of the time no matter what the temperature is set to. Maybe it does go off at times and I just haven't paid attention. Can you clarify what seems to elude my intellect?

 

I turn mine off in the spring and fall when I know that no A/C or dehumidification will be needed.

 

My AC is frequently used by the automatic climate control system during the winter in order to lower the humidity in order to keep the windows from fogging up. This is especially true when the system is putting out heat in order to warm the interior of the car if I have the defroster on.

As for the poster that was concerned with the AC reducing the MPG, that is not a major concern in modern cars with large engines. Old style ACs could indeed drop fuel efficiency by one or two MPGs, but modern ACs in cars with an engine the size of our 3.5 generally reduce fuel efficiency by less than one MPG, especially in cool or cold weather when they will not be operating full blast, and sometimes are simply idling.

Auto makers now design the HVAC systems in cars with the notion that the AC may be running most of the time during much of the year as part of the Automatic Climate Control system. This has been true for Maximas with Automatic Climate Control since the 1990s.

 

I still can't figure out why fans default to bottom instead of front. I usually switch to manual just so I can get some hot air coming out towards me

 

The default in Automatic Climate Control systems should focus on heat from the footwell vents in cool weather and cool air from the dash vents in warm weather.

That is because heat from the floor vents warming our feet during cool weather eventually rises and tends to concentrate in the upper portion of the passenger compartment, leaving our feet still not warm enough, but our head and torso increasingly hot. Very few folks would want the hot air also coming from the dash vents in cold weather, as it is not comfortable having the car stifling around the head and torso, while our feet are still cool or cold.

Likewise, in warm weather, the air in the upper part of the passenger cabin tends to get much hotter than the air in the footwells. So the AC wants to put the cool air through the dash vents, knowing cold air tends to sink, so will end up mostly concentrated in the footwell anyway. Nissan has this right.

 

Dropping knowledge!

 

That's what I was going to say. Lol

 

Yeah, what he said.