[rokyracoon]

When I press the "auto" climate control button, the default "mode" is the foot outlets only air flow. When I select any other mode, the "auto" light goes out. Is this normal or is this something to bring up to dealer service department. Of course the manual is no help.

 

[rlb330]

Mine does the same thing, so it's probably supposed to be that way. I'd be interested to hear if there was any way to change it.

 

[Kris]

mine is the same way. the air flow stream changes depending on heating/cooling and temperature differences between inside/outside. good news is that when you manually change the direction of air flow, despite the auto going off, the temperature is still maintained according to the settings.

 

[jpburk]

As I understand it, "Auto" means that the HVAC computer controls every part of the system....air flow, air speed, etc......based on the temperature you select. If you take control of any part of the system, then "Auto" goes off, and the computer relinquishes control of that option to you.

Jeff

 

[rokyracoon]

Thank you all for a your help. I fail to understand why the "auto" mode should contol which vents the air comes out. Well, nothing is perfect, but at least the HVAC works and that's what counts.

 

[Dookie]

The direction of air flow changes with the inside temp. If it starts at the feet, usually it will change to both upper and lower air flow, then can eventually change to upper only. It all depends on the inside temp. Same thing with the fresh and recirc. air--if it's hot out and auto is on, it should automatically go to recirc. then switch to fresh air when the inside cools down.

 

[Eric L.]

The auto mode starts on feet for you because its probably cold weather for you - the feet setting is most efficient for heating the car since warm air rises. If its a hot day, for example, the auto mode will default on the face setting. Once the interior heats up or cools down enough to be close to your desired temperature, the setting will default into the bilevel mode (face and foot).

 

[rokyracoon]

I had no idea that Nissan would do all the thinking for me. I personally would like to have a little more control over my car. Now I can go to the "What Do You Call Your Car" thread and name mine "big brother".

I want to thank you all for explaining the HVAC operation to me. Your knowledge is something they should put in the Owners Manual. I thank you again for knowing the answers.

Now, do you find the drivers seat comfortable or do you find some kind of bump in the cushion that happens to cut off the blood flow in your upper thigh? Just asking.

 

[Halo]

The stupidest thing (IMO) is that in AUTO mode the AC compressor is constantly running unless you disable it. At first I assumed the light on the AC switch when AUTO is selected just meant that the system would turn on the compressor when it needed it... but no. It will run constantly. So, think about it, if it's 50F out and you have the interior temp set to 72, the system draws in 50F air, cools it (with the always-on AC compressor) and then heats it again to try to get to your selected temp. LOL.

The manual tries to make sense of this by stating that the AC is drying the air. I usually run it in AUTO but immediately hit the AC switch to disable it.

 

[Eric L.]

The stupidest thing (IMO) is that in AUTO mode the AC compressor is constantly running unless you disable it. At first I assumed the light on the AC switch when AUTO is selected just meant that the system would turn on the compressor when it needed it... but no. It will run constantly. So, think about it, if it's 50F out and you have the interior temp set to 72, the system draws in 50F air, cools it (with the always-on AC compressor) and then heats it again to try to get to your selected temp. LOL.

The manual tries to make sense of this by stating that the AC is drying the air. I usually run it in AUTO but immediately hit the AC switch to disable it.

Yes that is exactly what I have noticed as well - in auto mode with the AC engaged, the compressor is on constantly. Looking at the shop manual - the Murano has a fixed capacity compressor, which means unlike other vehicles which have variable capacity compressors, the AC system does not go into a "reduced" mode when the air is already cooled.

 

[Dookie]

When I have mine in AUTO and A/C on, I can hear the compressor disengage and engage on a normal basis. Mine doesn't run all the time...

 

[Halo]

But what is making it engage in the first place? Unless your heating system is overshooting the internal temperature, there is no reason to be wasting the AC cooling the incoming air.

 

[Eric L.]

Exactly, there should be no reason. However, on a freezing evening, I start the car and push auto. I hear the AC compressor engaging. Now its just as cold inside the car as outside, why does the AC engage? Lousy design by Nissan if you ask me. I manually turn off the AC when I want just heat.

 

[msfiveiron]

This behavior of the AC engaging in Auto mode is not unique to the Murano. In fact, I believe that any car with climate control will engage the AC condenser, as it does indeed dry the air. My wife's 1996 Bonniville does the same things, as does my mother-in-law's '02 BMW. In many cars, it will auto engage when you turn on your windshield defroster, and you cannot turn it off. I remember my first car did not have AC, and it was literally impossible to keep the windshield from fogging up during a rain or snow.

Made it very difficult to cover your tracks after excessive backseat activity :22:

But seriously, this is common among cars with climate control.

 

[Snopes]

My '03 Ford F-150 SuperCrew engages the compressor in _all_ settings except vented air/panel vents. On a cold day with floor vents selected the AC starts cooling your feet before the engine warms up to provide heat. There is no way to disengage the compressor and this is not an auto type system. I hate it. At least with the Murano I can take control if I want to.

I like having dry air circulated. I'm sure it is better for the interior and for the ducts, and probably limits fungus and mildew. So in that regard, having the compressor run is a good thing. But for those of us with an inate conservatisim (not political) running the compressor seems wasteful of gas, etc.

Energy wastage aside (since it is probably irrelevantly small), the burning question is how does this affect compressor life? They are very expensive and where I live, not having AC is not a viable option....especially with leather seats.

George

 

[dklanecky1]

My 95 Maxima GLE had 190,xxx miles on it and the compressor was never serviced or replaced and the story is the same with my 00 Maxima SE which now has 137,xxx miles on it.

Compressor life shouldn't be an issue. This is assuming that the compressor is the same that's been in use for years on Nissan vehicles since the basic HVAC system has also been in use for years on various Nissans.

I can't imagine they'd mess with a part that has obviously been so serviceable over the years.

I also drive with the HVAC on auto practically all the time also.

 

[Snopes]

Yes, I've had pretty good luck with Nissan compressors.

'84 King Cab 4x4: compressor good at 140K miles
'90 Pathfinder 4x4: comprerssor failed at about 150K
'96 Maxima: compressor good at 170K

I'm not too worried about the Murano, its the F-150.

George:13: