I have an odd problem with a 2001 S80. AC works fine, Heater works fine but, when driving with a window open and temp controls on cold while the AC works fine there is a blast of hot air coming from the left side of the console at floor level. I've tried blocking the heat outlet on the left side but it still comes through although somewhat less. I'm stumped. Has anyone had this issue or aware of a fix? Thanks in advance, Dave Roper

 

assuming your S80 works the same as my old 850, there is always warm coolant running through the heater core - and the cabin temperature is controlled by air blend doors. The climate control system actuates the blend doors with different motors (I think there are 5 in total) to control airflow from the heater core and the AC evaporator. If you don't have any fault codes (ie blinking REC/AC lights etc) then the likely problem is one of the actuator motors has disconnected from its door (should be a rod to connect the door to the motor) or the door is mechanically stuck in position (lol, like a mouse nest blocking the door?).

 

I kind of was hoping it might be simple. I don't relish the thought of tearing into the dash, I've done enough of that thru work but it seems that might be the only option. Ive had the dead mouse in the heater in a Safari Van. NO FUN!