HVAC cold air flap?

[da96blan]

Need some advise. I got a LHD T6 and there seem to be some kind of cold air flap located near passenger side footwell. When I've been driving a while in hot weather, meaning the HVAC temp controls are set to low and fan speed is high, this flap seem to open which drastically reduce the cold air flow from the vents. There is a clear distinct sound of rushing air from the passenger side footwell - you can't feel the airflow so it must be somewhere behind the panels. It sounds exactly as the air is just openly vented directly from the HVAC fan. If I stop and turn the ignition off for a few minutes it usually goes back to normal and I get full cold air flow from the vents but then it comes back after some time - differs from time to time.
I do not have this issue in cold or moderate weather so it seem connected to running the HVAC on low temp settings. Does anyone have any idea of what this could be? Is it an intended function of the HVAC system to prevent overload or whatever, or is it signs of malfunction? There are no HVAC fault codes stored.

/Anders

 

[StratosFearXX]

Something to do with recirculate perhaps? I know mine gets louder from passenger footwell when recirculate is on so I presume that where it's sucking internal air in instead of external.

 

[da96blan]

Thanks, indeed looks like it's the recirculation. Apparently the system activate recirculation automatically if outside air temp is too high and in that case it does not necessarily illuminate the recirc light so I guess that is what's happening. Don't see why that would impact the cooling capacity though but might not be related - could just be that the HVAC cooling capacity in this vehicle is not really sufficient to provide enough cooling in very hot weather.

 

[StratosFearXX]

I don't think mine (2024 6.1) does that by itself and we've had some 32°C weather here recently (UK) ...

You're in Sweden I think? How hot is it there?

 

[da96blan]

I don't think mine (2024 6.1) does that by itself and we've had some 32°C weather here recently (UK) ...

You're in Sweden I think? How hot is it there?

This year I've experienced it only once a few days ago when it was similar temperatures as you indicate. But previous years I've been driving long stretches in europe in 30+ degrees and this sound of rushing air has been almost continous, from a few minutes after starting the car until you stop and turn of ignition. I've been certain something must be wrong but as no codes are present it doesn't seem so. The recirc flap sounds very reasonable so I assume that is what I am hearing.

Not sure if there is any way to force the recirculation flap to close if it has been automatically opened by the system? Next time it happens I will try to activate and deactive recirc manually to see if it makes a difference.

 

[StratosFearXX]

I think I've read somewhere that it will go into recirculate automagically if you're reversing to stop exhaust fumes coming into the van, haven't noticed mine doing it but if it does at least it would imply there is some automatic feature to recirculate. I don't know, vehicles are so complicated these days ...