The problem with the G35 sedan is that the automatic setting is setup incorrectly. It does not actually use the inside air temp to adjust the fan speed. It actually uses the outside air temperature. Therefore, when it is really hot out you need to set it about 10-20 degrees below what the outside air is and then adjust it yourself as the car cools down. This really defeats the point of the automatic setting doesn’t it? This is the only design problem I have with the car but it is becoming increasingly annoying. I live in North Carolina where it can get pretty hot! My car usually reads 107 degrees when I get in it at the end of day. That means that my AC is always on full blast on the auto setting until the car gets moving and the temp reading starts to get closer to the real outside air temp.

 

And how do you know that?

Why is that a problem? That is EXACTLY how the system should work. If it is very hot in the car, then the system is going to crank the fan and A/C until it approaches your set temperature. At that point it will back off on the fan and probably cycle the A/C as things stabilize. I don't know what you are actually complaining about here, but from a systems standpoint, sounds like it is working exactly as it should. The average comfort temperature is somewhere around 72 to 76. Don't you think the car would go full blast on A/C and Fan to drop the temperature by 30 degrees (107 - 77)?

 

I am not an engineer, but I wholeheartedly agree. Also, keep in mind that ones' PERCEPTION of temperature can differ with one's activity level and prevailing weather conditions. If I have just left the gym, a setting of 75 seems terribly hot. OTOH, if it's raining (no sun) and i've just left an air-conditioned office, 75 might seem too cool. I leave it around 70 and adjust up or down ONLY BY A FEW DEGREES. I have noticed that the system holds on to RECIRC for a rather long period, and I have seen it revert from OUTSIDE to RECIRC after the car has cooled down. Nothing's perfect-this is pretty close.

 

No the problem is that the fan will continue to run even after the temperature in the car has dropped below the temperature that you have the dial set to. I know this because I tried it. Go out on a hot day. Today it was 87 when I first got in the car. After driving the outside temp still read 83. I set the A/C gauge to 73. The air conditioning was not on full blast but it was on at least halfway. I drove around for about 20 minutes with the temp still set on 73. The result. The car was freezing. Now I didn’t have a thermometer with me but I can tell you it was well below the 73 degrees I had the dial set to. I will measure it with a thermometer next time. I checked the manual and it only mentions a thermometer in front of the radiator. That means that the only temperature that it can base the automatic setting on is the outside temperature. If you can find anything that says there is an inside thermometer please let me know where it is located. Until then I believe that the Automatic climate control is designed improperly and it is no where near as effective as the ones used in a Honda/Acura. That being said. I still love my G35.

 

I hate to sound simplistic, but if this is the case, then you need to put your setting at something higher (say 74 or 75). Why choose 73 if the end result is your "freezing".

Truthfully, you can't tell me anything without some kind of verification with a thermometer. However, I'd tell you to save your time, because you will most likely find that a cars air temperature is going to vary greatly around the cabin, becuase it isn't as efficient as a house. The point I'm trying to make with you is that you need to find the setting that is comfortable for you. Sounds like 73 is too cool, so try something warmer. Whether or not the numbers are 100% accurate is moot. The point is that the system WILL control to a number and you need to find that number that works for you.

 

My point about the thermometer is that if they do not have a thermometer in the cabin of the car then there is no way that they are controlling the air flow from the A/C based on the inside air temperature at all. Please tell me the location of any thermometers inside of the G35 sedan cabin. I could not find any indication that there are any inside the car in the user manual. Maybe there is but I could not find it. Without this then the design is flawed and the car can not regulate the temperature of the car at all. This is what is actually happening. Try it your self. If I set it to 76 when it is only 83 out then it is cold but not too bad. If I set it to 76 when it reads 107 out then it is down right cold in the car after running the A/C for awhile because the temperature difference is too great. Please prove me wrong on this point. I would love nothing more than to find a way to get the A/C to work properly. My wife can’t stand the fact that she has to keep adjusting the temperature when it is supposed to be automatic.

 

I do agree with you, that they'd be using some kind of fuzzy logic if there isn't an internal thermometer. I thought I remember reading something in the manual about one though. There are two sensors on the dash; I thought one was for the auto headlights and the other was the thermometer. Not sure though.

If that is the thermometer, then the next question would be where would the second one be for dual-zone control???? More fuzzy logic?

 

Most cars, with the exception of truly luxury cars, are not real climate control. My 99 328i Bimmer had a much better a/c/heating than the G35.

 

There is no fuzzy logic involved if there are not any thermometers in the car. It can not maintain an inside car temp without those thermometers. It would be fuzzy logic if they only use one thermometer for the dual zone because they are saying that both sides can be controlled independently. However, the controls assume that both sides of the car are at the same temperature. I think Infiniti decided that it was too expensive to do the Dual zone right so they just kind of faked it. I would like to know if it is true or not. Can anyone confirm that there are any thermometers inside of the cabin?

 

My 99 Honda Accord had one of the best A/C automatic modes I have ever seen. When you set it to 70 degrees the car would adjust the air temperature and flow rate to get the car to 70 degrees. It also would adjust the air temperature and flow rate based on the difference between what you wanted and what it was measuring at that moment. If it was 96 in the car and you wanted 70 then it would go full blast. If it was 71 and you wanted 70 then it would just barely turn on with 70 degree air. It did all of this because it had a well placed thermometer that was right near the steering column away from any of the air vents. It doesn’t have to be a luxury car to be designed right. Personally I am glad that Infiniti scrimped on the A/C and gave us all of the wonderful technology in that V6 instead.

 

All I have to say, is my GF's 2004 Mazda 6 has an inside temp meter (next to the steering column) and a solar sensor on the dash to adjust the inside temp. I would hope our G's have the same technology instead of relying on fuzzy logic. My 0.02. =)

 

I normally don't fiddle too much with my settings, except when I first get in the car. Parked outside my office, all day, on a typical Alabama summer day, the temps in the car can well exceed 120 degrees. When I walk out to my car, I roll down all the windows. When I get in, I drop it down to 60. I understand that in all likelihood the air temp coming out of the vents isn't any cooler than when the thermostat is set to say 70, it's just the fan speed. However, with the windows down, and the fans rotating at such a high rate, I can at least equalize the temps inside the car to that of outside by the time I pull out of the parking lot. At that point, I put it on a comfortable setting, roll the windows up, and leave it alone.

 

Whomever is getting the thermometer out to check this out - try something while your out there. Set the temp to 70 and then see what the temp of the air coming out of the vent is. Please also try it at 60 and at 75 or so. My theory, as mentioned earlier, is that the temp is the temp of the air it is putting out not the temp of the cabin. Maybe it is just my imagination that it feels colder to my hand.

 

This post is EXACTLY right. Let's face it, it is OBVIOUS from how the unit operates that it uses the outside temperature as a gauge for running the fan and cooling. This is an absolutely absurd way to design the unit. I guess this would be smart engineering if I like driving around in oppressive heat with my windows down, but I don't. Infiniti screwed up, probably to save money. Sure, I still love my G, and I'd still buy one even if I knew of this design flaw. Those of you who have experienced the fan AUTOMATICALLY slowing down as the temperature IN your car decreases either have a different system than me or are not describing the situation properly.

 

I trust the engineers when temperatures are moderate, but the Nissan automatic climate control systems I've owned (G20, Altima 3.5 and now the G35) get wonky at temperature extremes, particularly on the hot end of the scale. Setting the system to, say, 76 in the dead of summer in north Texas means you'll be getting a five-bar fan blast for at least 10 minutes as the system tries to cycle the cabin temperature down to a perceived 76 as read by the cabin temperature sensor. It's like being in a minor hurricane. Conversation is difficult, and if you're sensitive to temperature changes across your skin, you'll be unconfortable. Eventually the system calms itself down from spaz-o-blower mode, but until then the cabin is not a very pleasant place to be.

For my wife and me, it's much more comfortable when getting in the car in 95-degree-plus days to set the blower to manual mode, crank down the temperature to 60 degrees and manage it ourselves until the cabin cools down, then set the thing back to auto, raise the temperature to 76 or so and let the system take over. You engineers can be smart, yes, but you often have no common sense when it comes to the human component of a system. The Nissan automatic climate control system is a prime example.