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A/C problem

1977 Views 13 Replies 8 Participants Last post by  BobbyandRyan
It's already hot here in Florida and it';s the first real hot weather since I bought my car.
With the Climate control in auto mode and the temperature set to 70, when I start the car, the fan does not go to max like my 06 CTS did. If I want more rapid cooling I have to manually set the fan to max speed.
The dealer gave me the standard -they all do it that way, answer and said there was nothing they could fix.
It seems to me if the climate control system wants to get to the desired temperature as quickly as possible it would max out the fan and then regress the speed as the temp is achieved.
Has anyone else experienced this. I sure could use some help on this one.
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It really depends on the interior and exterior temperature of the car at any given time. When it's really hot inside and out, I'll usually get Max, but sometimes I won't. I've learned to let the car be smart about it - while my usual experience in my old vehicle was to just max the thing out, the CTS seems to be more intelligent about the fan speed that's needed to attain a desired temperature - and I learned to let it do its thing because no matter whether it's trying to heat or cool, it always seems to get the temperature down quickly regardless of how it does it, so I've stopped worrying about whether it's going full tilt or not.
Well, when I say hot, it's hot outside as well as inside. I'm basing my question on the inability to cool the car quickly, also my experience with my 06 CTS.
I recently purchased a 2010 CTS and have the same question/problem. My dealer gives me the old "they are all that way." My 2006 STS wasn't and my 2004 Corvette isn't. Did you ever get a satisfactory answer?
With a hot interior and the A/C on Auto, the fan on my '08 goes to max speed.
So does mine except the fan speed reduces quickly and doesn't maintain the desired temperature.
That's weird because here in AZ, my black CTS does amazingly well. It seems to choose just the right speed and amount of cool air to take it exactly where it needs to go. It's typically over 100 degrees here in the summer, not counting the interior car temp.
My '08 also does a good job of automatically managing the temperature and fan speed. I wonder if the fan speed algorithm was changed for later years?

If your car has been sitting in the sun with windows up and sunroof closed there is a lot of very hot air trapped inside and it is a good idea to let this super heated air out via opening your windows to reduce the heat load on your climate control. This will allow the system to reach the desired temperature far more rapidly. Using recirculate will also help it to cool much faster in very hot conditions.
Thanks to all that have replied to my problem. As with many problems there are a variety of views and solutions and not everyone experiences the same difficulties. I am a resident of Phoenix, AZ and understand the extreme heat that occurs inside a car that is left in the sun. It seems that should cause automatic controls to function at their highest settings and remain there until a significant drop in temperatures occurs. My fan speed reduces quickly and settles to a speed that is insufficient to reach the temperature setting. My dealer advises they have a call into GM engineering and will advise when they get an answer. If I get something of value I'll post it.
If you manually set the a/c with the highest fan speed, how cold does the air get? It could be that at the highest fan speed there is too much hot air flowing over the coil and the a/c unit cannot keep the refrigerant cold enough. So the automatic controls may slow the fan down to produce cooler air.
Good suggestion. I'll experiment with it this week.
I noticed today, with temps in the high 90s, the automatic fan speed, when I lowered the temperature setting to 60 degrees, was not as fast as when I manually increased the speed. The automatic speed was about two bars lower than the fastest manual speed.
It appears Government Motors has built the A/C in the 2010 CTS to operate differently than some previous products. According to the GM engineers mine is operating in the manner designed. To check this out I had my CTS and a near duplicate CTS parked beside each other. After setting in the dealer's lot overnight at 1:00pm the cars were started with the temperature controls set identically. They both started at the same fan speed and reduced fan speed identically. The only alternative is to operate the fan speed manually.
My 2010 does not display the problem I originally posted in my original post. It works very fast to attain the temp it is set for.
I have a 2010 and the fan does not rev up just as others have noticed. However, I was given a loaner 2011 and it does go to high speed. Another weird thing about my 2010 is that the drivers vents are warmer than the passenger - no clue on this but it is very noticeable. Set both sides to the same temp and the passenger is cool and the driver luke warm. Anyone have this issue?
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