02 S80 picked up a couple of weeks ago. Anyway the fan/ happened to be the ac came back on full blast after ther car had been tunrned off for about 1/2 hour. Had to turn the key on and turn the fan hi/low switch all the way off the turned the key back off. The very next day, before shutting the car off I turned the fan switch all the way off before turning the key off. It happened again.......... I'm at a lost is this going to be a dealer fix ? has anyone heard of this before and what fixed it? Thanks for reading. I also posted about an immobilizer message and suggestions there? I dont want to start dumping alot of $$ here.
Thanks for reading guy's

 

Its suppose to do that. The fan will turn on every so often to circulate air in the cabin. Next time wait and see if it goes off after a bit.

Jim

 

Is there a way to disable this feature so the battery won't drain?

 

I have an 02 S80 T6 that behaves the same way. And the response I got was the same as you did. But mine will stay on forever if I don't turn the key, same as you.
Question: have you done anything electrical lately...like replace the battery? I believe that there is some kind of battery re-set protocol. Some of the other guys here may know what I am talking about. I have to look it up because my car is doing it alot lately.
Florida Summer...wooohooo!