Hey guys,

I've had my 2005 Mustang since 2009, but I only noticed this recently. Even while my A/C is off, and hasn't been turned on for days, air will still blow out of the face facing vents and under dash vents (not the windshield/side window ones). The faster I go, the faster the air pushes out.

I know the A/C compressor is attached to the serpentine belt, but this seems a little much. It seems to match the temperature outside, but one time I did put the heat on for 30 seconds or so to test, and when I turned if off, warm air was still blowing out at speed (maybe just leftover).

Any ideas? Has this always been a thing, and I just never noticed it? I rarely us the A/C (unless going above 60). It's always windows down. Above 60 is windows up and A/C on. With it being cooler out (I live in Florida), I leave the windows up over 60, but have the A/C off. I ALWAYS have the vents closed when not in use, so a while back, I noticed a trickle of air coming out. When I opened the vents at highway speed, I noticed the issue. Based off of all that, it's possible I just never noticed it.

What do you think?

 

Sounds like you still have your vent fan on. If you are just pushing the AC button to turn off the AC, the vent fan is still working and pulling outside air in. It has to be turned off separately.

 

My 2008 has an actual off position on the selection ****, not the fan speed
****. So, when it's off, it's off...

 

Everything is off. I keep all the ***** pointed straight up (for symmetrical reasons), which is "1" on the speed, right in the middle of hot/cold on the temp, and "O" on the settings which is off. It's almost as if something it stuck open somewhere, and air is just rushing in as it pleases as the car moves.

 

1 is not off.

 

On a 2005-2009, that's the only option we have on the fan speed: 1-4. "Off" is on the settings ****.

 

You only have 1-4, then the vent direction "O" for off. There is no OFF on the fan speed selection.
If you have the vent position dial set at "O" then the fan is off. I have a 2008, and that's the
way it is for 05-09.


Changed in 2010:



Even when it's off, you can still have air flow through the vents, it's not an air-tight seal.
I have the center dash all apart, I took the Shaker500 out to try and fix it, and since
it won't fix I am not putting it back in. So, I have that all apart, waiting for all the parts I
need to come in. In this weather, went to the store, and I still had cold air coming in
a little bit, even with the fan off.

 

Gotcha! So I guess it's just a thing. I'm surprised I haven't really noticed this since I've owned the car for almost a decade. Haha. Thanks!

 

 

When the system it turned off, that gets turned off too. Even when you turn the A/C back on, that's off by default on 2005-2009s.