Sometimes after I leave my car for a period of time, I come back to find the blower running. Its not the fan in the front of the engine but the fan between the engine and the passenger compartment (i.e. A/C). Its only shuts off after I put the key in the ignition and move it to position #1.

I know the engine has a "turbo timer" where the fans keep going after the car shuts off to cool down the engine, but like I said, this is hours after I have shut off the car and when I did shut off the car, the fans weren't blowing.

 

It is a feature of the car to keep the interior cool when it hits a certian temperature. I have also heard that it does this sometimes to prevent frosting. The fan doesnt stay on indefinitely however as it will cut off long before it significantly drains your battery..
All in all, a rather smart feature if you ask me...

 

I believe that it is 45 minutes after shutoff... but I could be mistaken here...

 

As I understand it, the fan comes on to exhaust humidity from the cabin after the vehicle has been turned off...designed to reduce moisture issues in the ventilation systems. I believe that it comes on about 45 minutes after turning the vehicle off and stays on for only about 5 minutes or less. I assume that it is triggered by some sort of humidity sensor located in the climate control area (not 100% sure on this fact, but since it does not always trigger to come on, there would have to be some sort of triggering mechanism).

 

Thats good to hear. There was one hot day I came to the car and the blower was on already. It wasnt blowing cooling air like AC, just the fan was on. I was like, "K.I.T.T.???"

 

Was anybody able to solve this problem? The passenger cabin blower on my 850 GLT 1995 also turns on by itself intermittently even when the engine is off. It has drained my battery twice. Can this feature be switched off permanently.

 

I dont know about the 850 but in the S80 it is a "feature."

Its actual intended purpose as stated above is to remove condensation from the A/C condensor (or dryer I get the two mixed up)
Its supposed to only come on when you have been running the A/C (or defrost, anytime the A/C compressor has run)