Hello everyone thanks for helping me with my problem. I’ve searched the forum to find a solution to my problem, but I can’t seem to locate it. The heat on our 06 xc90 2.5T AWD will go from hot to cold to hot to cold to hot to cold, etc. But then sometimes the heat will work great with no problems. Thanks for your help.

 

Not sure if the XC90 has thermostat sensors like the older cars do but when they go bad they make the climate control go haywire. See if you can find them.

Usually the system will tell what is wrong with it but someone with a Volvo scanner will have to scan it and tell you.

 

An ECT won't cause that on an XC90 or even an 850.

You have a damper motor problem. They may need replacement and calibration or just calibration.

 

What's the temperature gauge showing when you notice this problem? Does the gauge fluctuates like the heat inside of your cabin? Is so, you have a tuck open thermostat.