AC Not Blowing Cold - All Components Replaced. The Infiniti service department has changed every component in the AC system of my 2003 G35 Sedan. They claim the refrigerant level and pressures are all good. Every time I picked it up it was not blowing cold air. I did extensive recording of air temperatures coming out of the vents. The passenger side blows colder than the drivers side, but neither one blows cold. I am suspecting that possibly there are dampers inside the dash which are somehow mixing hot air with the cold air and the result is almost no AC at all. Does anyone have thoughts on this?

 

Is your AC compressor cycling on and off?

 

No, it is not. I used thermometers and inserted them in the vents on the dash. When the outside air temp is near 90 degrees, the G35 can only supply air at about 70 degrees to the passenger side and 80 degrees to the drivers side. There is a difference in temperature between the two sides that is about 15-20 degrees. I have attached the chart I made for the Infiniti service department. I entered the data from my Cadillac ATS on the top two lines as a comparison. As you can see the air to the cabin for the Cadillac is at about 45 degrees. On my chart I alternated shaded and unshaded backgrounds to differentiate between trips taken during the tests.

 

Nice work on the documentation. If you don't already have it, the Factory Service Manual for your AC system is here:
https://www.nicoclub.com/service-man...2003%2Fatc.pdf
Scroll down below the viewing window and you can "click here to download a copy"

Maybe somebody can tell us - does that interior heater core always have engine coolant circulating through it or only when the AC system is calling for heat? Is there a plumbing valve involved or is it just done with the "Mode Door". Could the OP's problem could be that he is inadvertently getting heat along with cooling?

 

Thank you for the manual. Infiniti service advisor said he was "impressed" with my research and documentation, however, they still were unable to solve the problem. The manual sort of supports my position that there is something amiss in the climate control system as opposed to the refrigeration cycle. If the technician is correct that the pressures in the system are in in proper range, then as someone who is knowledgeable about refrigeration I know that the refrigerant temperature is in direct correlation with its pressure. So proper pressure readings mean there should be cold air exiting the evaporator. Therefore something has to be going wrong after that. As the manual shows there are a few doors that can be malfunctioning causing hot air to enter from the heater (as you are also wondering) as well as the driver side and/or passenger side doors as well. I am not savy (or young) enough to attempt to go into the dash board. I don't understand why Infiniti service department just can't figure this out. I always though that the dealership service department would be the best (and most expensive) to solve the problem. I wonder if an auto ac repair shop can handle this.

 

Your AC compressor should be cycling on and off if you have the correct pressures in your AC lines. If the compressor isnt working, you will never get any cold air.

Figure out why its not turning on. That will help point u in the right direction.

First thing I would try is to apply 12v to your compressor clutch wire and see if it clicks in.


If you dont wanna mess with it, take it to a shop that does AC work. Sometimes the guys working at the dealers are pretty dumb. The AC shop should figure it out pretty quick though.

 

Thank you for your reply however I'm not sure what you mean by the compressor should be cycling on and off. The compressor does come on as you can see by my temperature chart it does supply cool air to the cabin and but it's not cold enough and not bringing the cabin down to temperature. The compressor should stay on until the cabin temperature is at set point. It does not shut off because the cabin never gets to the set temperature. I think the fact that neither driver side or passenger side can supply air at 45° or so, plus the disparity in the temperature between the two supplies can be up to 20° difference indicates there are problems behind the dash. Most likely in the damper controls.

 

Yup. Check the blender door and actuator.

 

This thread might help:

https://g35driver.com/forums/g35-sed...vac-works.html

 

Scorpi0, thank you. Way too much for me to try to attack at my age (a 68 4r. old Scorpio), but, will allow me to understand it better when considering if I take it to a shop for repair.

 

Yeah the whole thing is kinda buried deep in there and looks like a pain to get to.

Im Nov 3rd btw….when is your bday? Just curious.