XC90 Fan Speed Control Knob Unresponsive
 

Car: 2005 Volvo XC90 2.5

Issue: Climate control fan speed knob does not respond.

Attempting to adjust the fan speed does not work. The knob does not respond when trying to regulate the blower speed. Periodically the fan will adjust itself (and the number of green lights will change) or I may be able to adjust the speed manually but then it goes back to being unresponsive.

I have uploaded a video to demonstrate the issue. If anyone has noticed a similar problem or can suggest diagnostics or parts I should check that would be great.

https://www.youtube.com/watch?v=3lY5Xfx9M60

The blower works on AUTO and defrost but I cannot manually regulate the fan speed.

Most of what I have seen in searching the forums is related to the blower not working and to replace the resistor and motor. The blower motor and resistor were recently replaced with new parts but this not not correct the problem.

Me Too!
 

I have an 04 and have had this same problem for what seems like a couple of years, did you ever figure out the problem?

My A/C also stopped working properly, I get a short initial period of cooling then just warm air, I don't think these are related?

Possibly your compressor clutch. Check if it is cycling on and off. If not, air gap may be excessive and will require adjusting.

Greg