Brand new Maxima. Love the car thus far. Only annoyance is that with cooler temperatures out (Tx.), I have the A/C off, just using vent, and the incoming air is almost "hot" at times, or at least much warmer than the air temperature outside. What's up? Anyone else experience this??

 

I have frequent bouts with the whole AC setup... it's one of the things that I really wish was different, and that I know I'm just gonna have to get used to.

I haven't noticed what you mentioned, but I really don't use AC off... I blast in either direction or open a window... What really gets me is the quirks in the system...

* "auto" for me automatically switches to the foot vents for some reason.
* Defrost should kick in at 100% and go back to whatever it was set when you turn it off (IMO), but it doesn't -- at least not in my car.
* Defrost also disengages the recirculate option, and forgets to set it back...
* Switching from "dual" to single mode doesn't use the driver's settings... I think it uses the highest temp... or lowest, I have to check. So if dual was set and the passenger was set at 72° but driver was set at 78°, turning dual off sets both to 72°

Again, maybe my car is just quirky... all I know is that this is how it behaves. Now that I've started to use the heat I might find some more stuff that I don't like about it...

 

There have been posts about this "warm air" situation in the past, and also on the G35 forums. The vent ducting under the hood picks up heat from the engine. If you're trying to save on gas by turning off the A/C, you're wasting your time ... the difference these days is so minimal that you'll never notice it. So, for me the answer is to never turn the A/C off. After all, it helps in the winter to keep your windows from fogging up and it removes excess humidity from the air. I keep mine on all year (and I'm over here in the Dallas/Ft. Worth area near you).

And, viguera ... switching "Auto" off should set the system to the temp selected by the driver, as it's the "controlling" side. And Auto will sometimes direct air to the footwells, depending on the outside air temp and the cabin temperature (mostly in winter and fall). But it shouldn't always do that.

And Defrost will indeed shut off the recirc, since it uses outside air to reduce the humidity inside the car. In fact, the main reason for windows fogging up is your breathing and body heat puts out more moisture than you'd guess, and it condenses on the inside of the windows. It probably leaves recirc off so the windows won't just fog up all over again. The message is that car makers don't want you leaving the system on recirculate very long ... carbon dioxide can build up, and if there's any kind of malfunction in your car, so could carbon monoxide and other toxic gases.

I've had a ton of cars with automatic climate control, including Caddys, Lexuxses and Bimmers, and I have to say the Nissan one works better than any I've had!

Mike

 

No matter the temperature, when I hit defrost it turns the ac on full blast cold.. ..it does clear the windows, but it is annoying!

 

Yeah I was talking about "dual" mode. If you switch it off, it doesn't always pick the driver as the controlling temp. Not sure why, but I'm sure there's a logic to it.

Maybe it's just done it when I noticed, but that's good information to know. I should go read my manual and see if it says anything about that...

That brings up a good point... recirc should turn off by itself, but I don't think it does. I'll have to check and see. I know it does on my other car, so I expected it to on the Maxima, but you make an excellent case for it getting turned off by the defroster. Although I still think it should kick in at 2000% rather than whatever the current fan setting is...

Well I'll take my MB climate control over the Maxima any day, but that's apples and oranges. I like defrost to mean "oh damn turn that thing UP right now!" -- max fan and max temperature, right now. I want my recirculate to turn off automatically -- and come to think of it, I want my heated seats to turn from high to low automatically too... but that's just picking nits...

 

For my Max, dual always returns to driver pref when turned off. Only recircultes when really hot and I want it cold, but goes to outside air pretty quickly.

So my recirc does turn off on its own. Whenever the desired temp is close to interior temp, recirculate disengages.

Goes to feet and/or top vents when temp selected is warmer than interior and/or exterior temp.

Defrost needs to be cold outside air otherwise it would add to the condensation. When you select DEFROST you turn off AUTO. Just hit AUTO again to turn the defrost off and recirculate will turn n again if needed (see above).

 

There has been posts in the past. Just lower the temp setting. One suggestion was set it at 60F. I found I didn't have to go that low. A/C will turn on but just hit A/C button to turn it off.

 

yes,flaw in the heat shield

 

I too have the problem that the vents blow hot air when turned to vent only, also when the whole system is turned OFF. My car puts out so much heat in this position that I doubt it is the heatshield issue. As you know, hot water from the engine constantly circulates through the heater core, and cabin set temperature control is accomplished by proportioning more or less hot air, from the heater core, in to the airflow through the HVAC unit. I was working on the theory that the air balancing door in the HVAC unit is not closing fully or partially, when the system is set to VENT or OFF(shutting off all hot air and directing full air flow from outside). This may be a mechanical problem or an electronic problem.
Maybe someone who understands the HVAC airflow can comment on this?