T5.1 Caravelle - What on earth is the air blowing out tube under the cab

[Soggy77]

Was wondering if anyone could help identify which part / system this is please

T5.1 Caravelle 2014 - 2.0 biTurbo

I have a fan running after ignition is turned off which there seems to be no rhyme or reason, and stays on for an age.

I have diagnosed and ruled out the following

1. NOT the radiator fan
2. NOT the HVAC blower in the cab or the rear HVAC system
3. Fan sound is near the passenger front wheel arch under engine
4. When fan is running Air is being blown out from a small metal Aluminium tube (Approx 25mm dia) under the car, about level with bulkhead, slightly to passenger side
5. Seems unrelated to temperature, happens in hot or cold conditions and if engine hot or cold.

Fan coming on when ignition is OFF, and seems strangely to be triggered if the doors are left open for a long time.

most recently it was OFF and when I returned to the van and unlocked with key remote, the fan started before as soon as doors unlocked
No combination of locking, double lock or unlocking etc stops the fan.


trying to identify as think it may be cause of the occasional flat battery
Hopefully someone knows what this system is so I can narrow down whichever sensor is playing up

thanks in advance
S

 

[roadtripper]

Do you have a diesel heater fitted? Your description of the vent sounds a bit like a heater exhaust.

Pictures will help.

 

[Soggy77]

HI. Thanks for response.

No aux heater fitted,
well pretty sure not - There are no controls for an aux heater but you never know, had the van for 3 years and I have been known to find features on cars after 5yr !!
I will try to get a pic under the van of the tube where the air blows out.

thanks

 

[z1ts]

If it's a 'Velle it'll have an aux heater (in my experience!)

 

[Soggy77]

ah OK, I just did a bit of reading.

So it could be aux heater, but just for the engine - not the cabin, and hence I prob may not have even noticed its existance
I will experiment with heater controls when its running and engine off - see if the coolant gets warm

at least if it can be pinned down to that system then its control or lack of can be investigated



cheers
S