Air Coming from Vents After Car Turned Off

DianaPrince · Post by **DianaPrince** » 13 May 2019, 18:24

Long question

2006 S60 2.5T

Got home from work today and went to turn my car off. Like everyday (out of habit) I turn the a/c and fan off, turn the radio off, then turn the car off and take out the key. Today, though, after I removed the key there was still air coming out of the vents; I could hear the fan running. I thought maybe the toggle for the fan speed was stuck so I started the car again, and tried to turn the knob. The fan speed stayed the same no matter which way I toggled it. I turned the car off again and took out the key—air still coming from vents! I thought maybe a fuse for the blower motor was bad, but checked it and it was fine. The only way to stop the air from flowing and keep the blower from running was to keep the fuse unplugged. I’m worried if I leave the fuse plugged in, the blower motor will keep running and drain my battery. Any ideas why this is happening??? Thought it was the evaporator function but it lasted for more than 7m. Help!

tardcart · Post by **tardcart** » 13 May 2019, 18:36

Im not familiar with whether the fan is computer controlled on your year. but on the earlier cars that would indicate an ignition switch problem (still in position 1). See if the radio and whippers also work with key off.

DianaPrince · Post by **DianaPrince** » 13 May 2019, 18:39

Radio and wipers do not work with key off.

tardcart · Post by **tardcart** » 13 May 2019, 18:52

nix the above, your car has evap. coil drying feature that will run the fan until it's happy.

DianaPrince · Post by **DianaPrince** » 13 May 2019, 18:57

I heard about that. But when I timed it to see how long it would run, it went over 10m. I pulled the fuse because I didn’t want to drain the battery.

Post by **Rattnalle** » 13 May 2019, 23:21

tardcart wrote: ↑13 May 2019, 18:52 nix the above, your car has evap. coil drying feature that will run the fan until it's happy.

That one waits a bit for the evap to warm up again then blasts some air through. It doesn't go low speed for ten minutes. Uses too much battery.

But also yes everything in the car is computer controlled. The position of any controls when you turn the car off is irrelevant once the car is off. You get fan running at I with manual fan speed set but only at II on auto, that's it.

Post by **abscate** » 14 May 2019, 06:34

The after-run is about 10 minutes, so unless it is running for hours, I would not worry about it. Since these cars use PWM and not resistor packs, the current draw on the fan at low speed is probably pretty low.

They could be metric minutes, or perhaps climate change has stretched time again, too.

Your ECC controls are all disabled for this mode - the car has taken over and hopefully does not become self aware like elephants, crows, and a certain Russian Blue Cat I have.

Do you rent out your Lasso of Truth? We need it here on occasion,

DianaPrince · Post by **DianaPrince** » 14 May 2019, 07:08

So how can I tell if it’s just the evap system or something else? I read in another thread on here somewhere that the evap system only kicks on 50m after car is shut off, and runs for about 7m.

I bought a new blower motor resistor just in case. I’m hoping I don’t have to install that because it seems like ...a lot of fun.

Got to work today after running a/c on the drive in, and didn’t have any issues when I turned the car off. Not sure if it’s a fluke or if the conditions weren’t right for the evap system to kick on.

Post by **abscate** » 14 May 2019, 07:13

DianaPrince wrote: ↑14 May 2019, 07:08 So how can I tell if it’s just the evap system or something else? I read in another thread on here somewhere that the evap system only kicks on 50m after car is shut off, and runs for about 7m.

I bought a new blower motor resistor just in case. I’m hoping I don’t have to install that because it seems like ...a lot of fun.

Got to work today after running a/c on the drive in, and didn’t have any issues when I turned the car off. Not sure if it’s a fluke or if the conditions weren’t right for the evap system to kick on.

I can tell you my 1999 sometimes after-runs the climate fan (not evap system, thats something else!) on key off, and sometimes an hour later. There is obviously some code with multiple inputs that determine when it runs.

I know Im an optimist at heart, but you can overthink these things, Electronics are really reliable, and usually trouble is proportional to how much we 'fix' them.

Post by **oragex** » 14 May 2019, 08:07

Try to monitor they days when it keeps running and the days when it shuts off with the engine. Could there be a difference in the outdoor temp that makes the computer think on some days the evaporator needs dried off more? I would guess the cooler days would need the fan to stay on because the cooler temp won't help dry off the evaporator fins. My experience is I got that mushy smell from the AC after running it in cooler days (my car doesn't have the setting to run the cabin blower to dry the evaporator).

As for the car battery, if it's in good condition, worry not about the cabin blower running for 10 min, it won't discharge the battery. Only a weak battery will suffer from this

If you go the resistor route, here's a fun trick: you can actually undo the underdash black cover, then undo the cover under the blower, and access the electrical connector to the resistor. Without removing the blower, undo this connector and plug it in the replacement resistor - let the resistor hang in the air. This way you can test see if the original resistor has an issue, without actually removing the blower.