I've had my 2010 for 14 months and have driven 13,500 miles, with the air always on. No problem so far with the air blowing warm air, but it has the worse auto air of any car I've owned. The air is always cold, but tends to get too cold where you have to constantly adjust it when on a trip, might as well not even have an auto sysem.

 

^havent had any issues with mine either. always blows arctic cold.

 

Mine doesnt really blow warm but there is a very noticeable temperature change when stopped at a red light. It seems to happen when the RPM drops to around 500. The air doesnt get hot, but its not as cool as it would normally be. The A/C in this car is very cold. I set the temp to 75(AUTO) and leave it there. I have the vents pointing to the ceiling. Otherwise I would freeze.

 

I took the car back to the dealer and had a tech ride with me. I was finally able to recreate the problem with a tech in the car. I stopped at a traffic light and the air from the AC started getting hot. We tried all of the AC controls, lowered the temp control switched from recirculate to not, etc. to no avail. The tech got out, looked under the hood and verified that the AC compressor was disengaged (not spinning). Put the car in neutral and the comp engaged and started cooling again. Then we started to notice that every time the AC stopped working, the car was idling around 500RPM. It should be 650-750RPM? They are going to reset the computer and let it relearn the idle to see if that corrects the AC issue. I was so focused on this being an alternator or AC system issue, I didn't notice the intermittent low idle. BTW, the car idles smoothly at 500RPM. Your tachometer should show the car idling just above the 500 mark. My car normally idles at the normal rate but intermittently idles low for some reason.

 

I've attached a PDF copy of ITB10-051 A/C BLOWS WARM AT IDLE for anybody who needs it.

My 2010 G37x does this every once in awhile, usually at the first stop light on my way to work after a cold start. This TSB appears to say it only applies to 2WD G37's, so in my G37x this may be related to the low idle speed issue Gpimptastic described.

 

Yeah, I know... I set mine to 75 degrees and it damn near freezes my **** off.

 

Have an 08 coupe (early build) 4years no problem at all.
Then had 2 a/c blower motors in a week.
1 month left on warranty.

 

I had the tsb done on my car and now no more warm a/c when stopped at a light. The RPM's no longer drop below 600 so the compressor never goes off due to low idle.

 

Mine was doing the exact same thing.

 

The dealer applied ITB 10-051 just as DocJohn posted. I have been driving the car for a couple of weeks and the problem has not reoccurred. I am going to go ahead and call it fixed.

 

Thank you so much for posting this! My car suffers this AC problem. The Technical Bulletin applies to 2010 G37 non-Sport Sedans and Coupes with 2WD and 7AT. I'm getting it fixed on Wednesday.

 

bump...

I'll need to keep the TSB in mind again. We've had a couple of warm days none super hot really and it was taking a while for my car to get cold, but I don't recall if it was just at idle. Now I'm wondering if my freon is low from the factory or a combination of it being low and the ecm needing to be reprogrammed.

 

I was going to post an observation about the A/C - might as well join this thread. No issue of it getting warm - in fact, just the opposite. It's cold as ice.

I assume it has a 'sun load' sensor on the dash...or something like that. On cloudy days, it seems to regulate the temperate fairly well. But when the (Texas) sun is beating down on it, it switches to 'meat-locker' mode and tries to freeze my face off. I point the vents to the ceiling and it's not too bad - but I also turn up the temp to far higher than I have ever had to on other auto temp units. Example: I would keep my Murano at @72 degrees and never have to touch it. But on the G - I have it at @77 - then have to roll it up to @80.

Just an observation of what seems like a mistake in the design...

 

^I agree. The A/C also blows harder on the fan speed one than any other car I've ever had. I just like to have some air moving in the car to keep it from getting stuffy, but when the fan is set to it's lowest speed it's pushing out a ton of air.

 

I believe the sunload sensor is the culprit. At night the auto a.c. works fine. I also think having tinted windows affect the sunload sensor. In loaners that I have driven I've noticed the auto a.c doesn't freeze my **** off. The only difference between my car and the loaner is I have tint which help to keep the car cooler. When the sunload sensor detects sunlight it increases the fan speed in an attempt to compensate for the possible increase in temp due to the sunlight entering the car. With tinted windows, less sunlight enters so less compensation is needed. Unfortunately, the a.c. system doesn't seem to know this. I have 5% tint all the way around minus my windshield. Sometimes I have to set my auto a.c to 80 to keep from freezing. The auto a.c in my maxima was not like this.

Just my theory. Any one without tinted windows have this problem??