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Dual Air Conditioning Temperature Difference

My 2003 Volvo XC90 has an air conditioning problem. The driver’s side is cool while the front passenger’s side is warm. Air seems to blow out strongly. I checked the temperatures today when both sides were set at 64 F. Vent temp is 55 F and 57 on the driver’s side (middle and left side dashboard vents) and 77 F and 84 F on the passenger’s side (middle and right side dashboard vents). I’ve brought it in twice to be fixed this year (just bought this year). Once they replaced the motor and adjusted dampeners. Second time they updated software and adjusted dampeners. For sure, the second fix two days ago did nothing to help. Q1. What would be the normal difference in the tempertures (2-3 degrees seems reasonable to me)? Q2. Any ideas about what is wrong?

One would hope that someone can answer this better than I can, but without having carnal knowledge of the Volvo HVAC system, the best I can say would be take it back and raise hell.

The problem must be in the control unit, the temperature sensor, or the servo that controls the temperature to the driver’s side of the car. It sounds like the place that you’re taking it to (Volvo dealer?) is not really doing a lot of diagnosis, otherwise they wouldn’t be sending it back to you without fixing the problem.

They need to make sure the driver’s side temp sensor is working correctly, make sure that the control unit is commanding the blend door servo correctly, and make sure that the blend door servo is reacting properly when commanded. That’s pretty much all there is that can be problematic here!