air con - what exactly is going on...when on?

[minmax89]

What is actually happening when you switch on the air con? I have standard stuff, not climate control or anything.

When I get in the van at the end of a hot day and it stifling in the cab, I turn the temp right down, switch on the blower to about 3, and press the air con button. I've never had a vehicle with aircon before. but after about 4 minutes of driving, a second louder fan comes on somewhere under the glove box. Why is that then?
Also, when I put it into reverse, some fan under the dash again goes into turbo mode! Its all a bit bizarre. Can anyone explain to me what is going on?
One final question is how do I know if my air con is working in tip top form? As in, getting as cold as it should.

Thanks!
Adam

 

[Spaghetti]

When you reverse, it automatically turns on recirculation mode so it recycles the air in the cab via a flap valve, to avoid sucking in exhaust fumes. The tone of the fan changes when this happens.

 

[Pete C]

It sounds like the fan is going into re-circulation mode automatically.
Does the light on the switch for this come on ?

Pete

 

[Rich Green]

When you reverse, it automatically turns on recirculation mode so it recycles the air in the cab via a flap valve, to avoid sucking in exhaust fumes. The tone of the fan changes when this happens.

Wow I’ve always assumed mine had a random fault never even considered that

 

[minmax89]

It sounds like the fan is going into re-circulation mode automatically.
Does the light on the switch for this come on ?

Pete

No, no light comes on. I'm not sure I even have a light on the recurculation button? Will check today.

 

[minmax89]

When you reverse, it automatically turns on recirculation mode so it recycles the air in the cab via a flap valve, to avoid sucking in exhaust fumes. The tone of the fan changes when this happens.

Ahhh! Thanks! I thought it might have been that alright.

 

[Dellmassive]

Got a pic of the buttons?


Heres ours.

 

[rover220]

It will automatically switch to recirculation if it needs, it will not put the light on in these circumstances

 

[minmax89]

It will automatically switch to recirculation if it needs, it will not put the light on in these circumstances

It seems that this is correct. Also after a test just now it seems you cannot switch on the recirculation when the AC is on

 

[Spaghetti]

It seems that this is correct. Also after a test just now it seems you cannot switch on the recirculation when the AC is on

You can use the re-circ with the AC but just not when it’s pointing at the windscreen (for demist)

 

[minmax89]

 

[rover220]

You can have recirc with ac on no problem.

 

[Spaghetti]

As it’s on the windscreen, it won’t allow recirculation. Try it in a different position.

 

[Rich Green]

So it seems your ac is on when the lights on but it also can be on when it’s off. The recirc is on with the switch unless it’s off with the ac on which maybe also off. Cheers VW it’s all so clear now

 

[Pete C]

So it seems your ac is on when the lights on but it also can be on when it’s off. The recirc is on with the switch unless it’s off with the ac on which maybe also off. Cheers VW it’s all so clear now

Sounds about right. I have had other cars where the vehicle would take control of the aircon and recirculation, but at least it told me it was doing this, by turning the relevant lights on.

Pete

 

[Evgenij Webster]

When you reverse, it automatically turns on recirculation mode so it recycles the air in the cab via a flap valve, to avoid sucking in exhaust fumes. The tone of the fan changes when this happens.

My van stopped doing this recently, so every time I reverse I choke on exhaust fumes. Any advice what isn’t working properly and what part might need replacing?

 

[Spaghetti]

My van stopped doing this recently, so every time I reverse I choke on exhaust fumes. Any advice what isn’t working properly and what part might need replacing?

Worth checking the flap moves when you switch it manually first. If not, servo or switch?

Check your reverse lights are coming on. If not, maybe reverse light switch.

Quick scan for codes may help too.

 

[Evgenij Webster]

Worth checking the flap moves when you switch it manually first. If not, servo or switch?

Check your reverse lights are coming on. If not, maybe reverse light switch.

Quick scan for codes may help too.

thank you uh for the reply.
I’ve Carista. But I am no longer a subscriber to it, so not sure I’ll get the info I need from it.

I will give it a go in a manual mode. See what happens. How easy it is to replace servo, where is it located at?

Ev

 

[Spaghetti]

It should close off the air supply from the outside. I can’t remember whether it can be seen easily from behind the glovebox. You can normally hear the tone of the fan change.

It’s near the fan motor/pollen filter behind the glovebox.

 

[Evgenij Webster]

So on the button record works fine and I can clearly hear audible change in the cabin when the presumably flap closes the intake from outside. However in reverse there is only a minor change and I instantly get exhaust fumes in the cabin. Where previous it was a notable audible change with a bit of a thud from the flap as it shut quite quickly. The reverse light work fine too, as I’ve upgraded them to LED in order to see where I am reversing into when looking into a rear view mirrors.