Cabin thermostat has a mind of its own

Tiny
OREGONFANLISA
  • MEMBER
  • 2007 VOLVO C70
  • 51,000 MILES
I set my A/C to always run and expect it to cool or heat at whatever temp I set it to. However, I find that it ignores what I want and does its own thing based on the outside temps.

For example, it is 40 degrees outside. I set my thermostat to 68 because I don't want heat. Well heat is what I get, and a lot of it, until I reduce the thermostat to 58. I have never had a car that I had to monkey around with the temperature indicator as much as I have to with thus car, my first Volvo.

My dealer says its no big deal and I should just live with it. However another Volvo expert informed me that my model's year called for a software update to correct this known issue. I cannot find evidence of this and my dealer denies it. What's going on?
Tuesday, November 8th, 2011 AT 5:24 PM

3 Replies

Tiny
BILLYMAC
  • MECHANIC
  • 2,204 POSTS
Hi, well this is quite a delimma. The expert that told you that prob is not avail or you have no way of contacting him.I would contact another dealer that will take the time and search recalls and tsb issued for this prob. Simply just telling you he is unaware of any such recall or tsb just is not good enough. Sometimes it is the serv desk job to weed out problems that may not be easy for the tech to find. They all have acess to volvo files so make them use that acess. Good luck
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Tuesday, November 8th, 2011 AT 6:08 PM
Tiny
JIS001
  • MECHANIC
  • 3,408 POSTS
It all depends on the system that you have? You most likely have electronic climate control (ECC) so the climate system is doing what it is suppose to be doing if you are setting it in auto? If the outside temp is 40 degrees and you set it to 68 degress then The heater is coming on to bring the cabin to 68 degrees and if it were the summer time and the outside temp was 92 degrees outside then the A/C would kick on to bring the cabin to 68 degrees. There may or may not be a CCM software update but I really dont think that is going to do anything for you? If you have a faulty ambient temperature sensor then you most likely have an issue with the A-Pillar harness fretting? In this case the outside temp could be 80 degrees but the ambient temp says it is 38 degrees? So guess what you will get in a nice hot summer day? Nothing but heat? And I have seen this a few times? So if this seems to be an issue then I would recommend you use the climate system in manual mode where you adjust the heat or cold air to what you feel it is right? Other then that I would say there is no problem and the expert is just wrong? And yes I work at a Volvo dealership ;)
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Wednesday, November 9th, 2011 AT 5:40 AM
Tiny
JIS001
  • MECHANIC
  • 3,408 POSTS
Selecting a temperature that is higher or lower than necessary will not heat or cool the passenger compartment faster.

I hope this helps and if you have any other questions please let us know.
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Wednesday, November 9th, 2011 AT 5:44 AM

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