The car is a 2000 S70 base model with dual zone climate control (where there are two dials that control temperature one for the driver and one for the front passenger).

The passenger side only blows hot air, regardless of where any of the dials are pointed. In automatic mode, half fan speed, full fan speed, full hot, medium tempurate (72), full cold, main vents, floor vents, both main and floor vents, it doesn't matter. All of the passenger side vents only blow hot air, which is more noticeable of an issue since spring and summer are fast approaching, and I carpool a good bit so its nice to have cold air for my friends/family. All of the driver side vents blow according to the temperature dial, so they work fine.

I read that blowing full heat for 30 seconds "resets" the system and it works fine again for a while, but I tried that on 3 separate occasions and each time it did not work. I also read that the passenger side usually goes first and then the driver side follows soon after. I never found any solutions though.

If anyone knows what might be wrong I'd immensely appreciate any advice.

-first477

 

Most likely the blend door motor. When it stops moving the door and gets stuck on drawing air through the heater core all you ever get is heat. Of course there could be other problems like the control unit or wiring, but I would test the motor first.

 

Okay, hopefully that's what's wrong. I'll update the thread once I check it out.

 

The motor is hard to reach on the passenger side of the center air box. There are two on that side, one up high (easy to reach) and one down low, you will likely need some kind of flex extension to reach the T15 screws.

 

Thanks. I'm not used to taking stuff apart, and I've been busy, so I'm putting off looking at it. I don't know if would be the actuator or the motor either, so I kinda want to replace the whole thing.