HVAC goes offline restart tends to fix!?!

carboncow · Post by **carboncow** » 27 May 2011, 15:11

Again, troubleshooting for a family member her 2007 T6 XC90 as I know more about V70s....

She states that the HVAC system goes offline...she has lost heat and cold at times. I have replaced several failing fans in many vehicles and know the syptoms tend to be irregular fan speed, squeaks, behavior changes when going around corners and intermittent on/off/on behavior.

She claims no concern such as the ones I mentioned. She believes the lights went out for the HVAC control panel...but isn't 100% sure. She believes that each time restarting the vehicle allowed it to work again.

Is there a common failure trend with the control unit or connection?

Post by **jimmy57** » 27 May 2011, 17:03

2007 xc90 had a software reflash to fix that on 3.2 6 cylinder models.

carboncow · Post by **carboncow** » 27 May 2011, 17:11

Since I've never taken a "used" car to a dealer before...I'll assume they charge for such things when the vehicle is out of warranty, correct? Anyone with the Vadis can do these type of flashes too?

TexasCoder · Post by **TexasCoder** » 27 May 2011, 18:17

carboncow wrote:Since I've never taken a "used" car to a dealer before...I'll assume they charge for such things when the vehicle is out of warranty, correct? Anyone with the Vadis can do these type of flashes too?

If I am not mistaken, It's going to be a dealer fix. The software "flash" is actually compiled and downloaded from Volvo servers, so it requires an active dealership account and the software package to be "compiled" with the necessary option. But I could be wrong, there may be technicians out there with means to compile a patch and push it to the volvo.

Post by **jimmy57** » 27 May 2011, 19:07

Only dealers and independents with VIDA can do it.
There will likely be a charge as I think this wasn't a recall or any other type of action like that.