[bigbman]

When I use the Auto button on my dash, it only uses the floor fan. Trying to swith it to anythig else turns off the auto temp. Is this the way it's supposed to work?

 

[njjoe]

When I use the Auto button on my dash, it only uses the floor fan. Trying to swith it to anythig else turns off the auto temp. Is this the way it's supposed to work?

When set on AUTO, the system will automatically control the fan speed and air distribution to maintain the temperature you select. Pressing the MODE button or manually changing the Fan Speed will turn-off the Auto mode.

There is only one fan for the whole system. A set of diverters controls the air distribution.

On my car, when the outside temperature is in the 30s and the engine is first started, the HVAC system will divert air to the foot outlets at low speed until the engine warms up. Once warmed up the fan speed will increase. As the temperature in the car approaches the desired temp, the fan will slow down and some of the air will be diverted to the 4 dash vents. The system will then maintain the desired temp.

Except for the occasional tweak of the temperature knob, I never have to change the settings. I always leave it on AUTO.

-njjoe

 

[zebelkhan]

Auto setting will operate all vents. However, its logic will take control and if it only runs the floor vents it is because it finds it necessary to do so. After a while it will switch to combination of upper and lower, or just upper vents. Changing the controls manually will kick it out of Auto.

I just remembered at times I have had the vents on floor and fan on full (Auto Off) but after a while it has automatically kicked back to Auto changing the vent setting on its own. Now that is confusing...

 

[Eric L.]

To add to the good posts above, the logic for sending air only to the floor vents is because when its cold, hot air rises, so it should be sent to the lowest location first. If the heater used the face vents only, you would have toasty ears, but frozen legs.

 

[zebelkhan]

...If the heater used the face vents only, you would have toasty ears, but frozen legs.

:19:

 

[nissanlove]

i've had experiences that the auto mode dosn't work very well in cold weather on long trips. the glass starts fogging up and air only blows from the floor and consol vents. i'm my aunt's 300M special, onced the desired temp is reached, the ACC switchs to front window and floor.

 

[Gonzo]

I just remembered at times I have had the vents on floor and fan on full (Auto Off) but after a while it has automatically kicked back to Auto changing the vent setting on its own. Now that is confusing...

Remember when the auto light is on the system is in FULL auto... as you manually over ride settings the you slowly remove auto capability from the system.

So you have started off by pressing AUTO and then you manual select the mode the system still has control of the fan. After you make changes to the fan speed the system has now lost control of the mode AND the fan speed.

I find the system works pretty good.

 

[mgthe3]

I don't use auto mode. I kinda don't like machines deciding on how I like my fan speed.
But---when I set the temp (usually 68 for me) the system will send warm air to the lower vents first until the interior warms, then it does a combo of upper/lower vents. This keeps the fog completely gone from the windows.
Also, if you flick the AC switch on, it will effectively dehumidify your interior while blowing warm air--thus giving fog no humidity to form from.

I'll never forget the time me and my wife went to the mountains (Gatlinburg) with a friend and his wife. It snowed while we there there and the temps dropped down pretty low. We went out in his Honda and drove around in the snow, stopping occasionally to get out and play a bit. When we got back in the car the heater would be blasting and it felt so good---until the snow on our boots etc started to enrich the humidity inside the car, forming fog on the windows---then we would freeze our a$$es off. I looked up to see he had turned the temp control waaaaay down and had the AC on---I said WTF d00d--we're freezing!
The dam honda refused to turn on the compressor unless you had the temp turned down close to ambient temps!
Needless to say, I never let him drive again on winter outings.

 

[Gonzo]

I like the auto fan when the car is first warming up... I just wait for the MO to determine when the coolant is warm enough and then it kicks the fan on high.... ahhh nice warm air to take the chill off.

Thank you MO.

 

[zebelkhan]

...So you have started off by pressing AUTO and then you manual select the mode the system still has control of the fan. After you make changes to the fan speed the system has now lost control of the mode AND the fan speed.

This the sequence that I use:

1- Press Auto
2- Press A/C to turn ac off
3- Turn fan to full blast
4- Press mode to set it to floor vents

It works fine for a while then all of the sudden (I am assuming a certain inside temprature) it switches the mode setting to both dash vents and floor!

My fix is to again press the mode key to get it back to floor vents. It appears that now it will stay there but I have never used to car long after the second switch so I am not sure if the "auto" mode would take over again...

 

[Gonzo]

This the sequence that I use:

1- Press Auto
2- Press A/C to turn ac off
3- Turn fan to full blast
4- Press mode to set it to floor vents

Odd you have full control... I can't image why the system is setting the mode when you have over ridden it. Are you sure you selected floor as if the system is heating it would have already been select so perhaps you didn't selected floor?

 

[Eric L.]

I have noticed the "system has a mind of its own" issue as well. When it is really cold, and snowing, I need to keep the defogger on to keep the windows from fogging up. For short drives, this is fine. But sometimes on long drives, the defog setting will switch automatically to bilevel (foot and face), and even though the AC is still on, this allows the windshield to fog up once again. I have to hit defog again to switch it back. And the 'auto' setting isn't even involved in any of this!

I've also occasionally seen (again on long drives on cold days) that if I set the system to auto, say at 65 degrees (I like it cool, even if its freezing outside) it will first blow on floor, then bilevel, and then after a while it switches to defog/floor. I don't mind this per se, except it will still do this if I manually switch off AC (but still in auto). When the 'auto' setting goes to defog/floor, my windshield fogs up immediately, and this is very annoying.

 

[bigbman]

Thanks for all your replies guys. Now that I've paid attention, I realize that auto mode does change from floor to regular fans (or both) depending on where it's needed. Turns out my Murano is doing what it's supposed to do!

 

[zebelkhan]

...Are you sure you selected floor as if the system is heating it would have already been select so perhaps you didn't selected floor?

You may have a point here. Although I go through the routine, once in a while if the mode setting is already on the floor (when in auto), I have never paid attention to see if I still cycle it and stop on floor again. Maybe that is it? It may not consider it a manual override unless I cycle it.....gooooooooooooooooood point

 

[mgthe3]

I just tested my anti fog thing.
It is 37 here and raining pretty good, perfect time for fog conditions.
Fan on 80%, temp set to 74, no AC, no touchy the mode button: while I was moving I had some fog but very little.
My wife ran in the costco for a drive by milk run and I sat between handicap spaces waiting for her with the engine running. In less than 2 minutes, here comes the fog. I reached over and hit the AC button and in less than 1 minute, no fog. Same temps blowing--but no fog.
:2:

 

[Eric L.]

I just tested my anti fog thing.
It is 37 here and raining pretty good, perfect time for fog conditions.
Fan on 80%, temp set to 74, no AC, no touchy the mode button: while I was moving I had some fog but very little.
My wife ran in the costco for a drive by milk run and I sat between handicap spaces waiting for her with the engine running. In less than 2 minutes, here comes the fog. I reached over and hit the AC button and in less than 1 minute, no fog. Same temps blowing--but no fog.
:2:

I once used a Rain-X antifog treatment on my windows on the Maxima, and that stuff worked. Except it left a film of its own, which kind of defeated the purpose or having a clear window.

I cannot tell you how many times I've been a passenger in someone else's car and the driver doesn't know how to defog the window by switching on the AC.

 

[njjoe]

I just love when you are driving on the highway on a cool, damp evening, and you pull up next to a car full of people that has all the windows fogged up. The windshield wipers are flying but they are useless against the inside moisture.

Usually this happens because the driver has set the HVAC control to RECIRCULATE the air, instead of bringing in FRESH air, and he/she has the A/C turned off.

I can't help but laugh ever time I see that.

(mgthe3- Parking in a handicap zone without the appropriate permit is a no-no. It doesn't matter if you are "parked" or not. I would hate to think a forum member would even consider doing such a thing. Right?)

-njjoe

 

[zebelkhan]

(mgthe3- Parking in a handicap zone without the appropriate permit is a no-no. It doesn't matter if you are "parked" or not. I would hate to think a forum member would even consider doing such a thing. Right?)

Yaah, and if you do it again OhioMurano will get you.....

 

[Gonzo]

I just tested my anti fog thing.
It is 37 here and raining pretty good, perfect time for fog conditions.
Fan on 80%, temp set to 74, no AC, no touchy the mode button: while I was moving I had some fog but very little.
My wife ran in the costco for a drive by milk run and I sat between handicap spaces waiting for her with the engine running. In less than 2 minutes, here comes the fog. I reached over and hit the AC button and in less than 1 minute, no fog. Same temps blowing--but no fog.
:2:

In those conditions the only way to remove the fog (humiditiy) is to turn on the AC.... the other fog, what I call dry fog, is when its really dry and cold outside you might get fog inside but that can be removed is the fresh air vent is on and there is airflow early on.

 

[mgthe3]

(mgthe3- Parking in a handicap zone without the appropriate permit is a no-no. It doesn't matter if you are "parked" or not. I would hate to think a forum member would even consider doing such a thing. Right?)

Well.....I guess technically I was in the zone---but I felt much better being in the striped buffer between the parking spots. If a van with wheel chair access door would have pulled up I would have moved--if not for fear of being bashed by their doors. Besides, I was in the furtherest one from the store...and, no one was in any of the handicap spaces.
My Dad has a Handicap rear view mirror permit he is always trying to give me---I could always do that like others do.....naaaa, no I can't, been turning him down for a decade.