Weird Aircon Behaviour. . . .

[::SPG::]

Had my 2006 B6 now for 5 months, it has the split zone climate.

Now we're driving down the A1 yesterday and I have the A/C set to 18 Auto but to be fair it is very chilly at that temp (how do others' cars compare at that temp?). So I set vents to face and turn fan to max, I can hear the fan speed increase but no increase in air flow at the dash vents, nothing at all. I go back to auto and repeat, same effect, nothing.

Weirdly if I switch the A/C off for a couple of minutes and then turn it back and try to set to face and max it works! But after a little while it stops doing it.

I have notice that I do have potentially excessive condensate drain off and I have check the pollen/cabin filter which is black so will get replaced this week.

Any thoughts?

[phil miller]

hi mate if the cabin/pollen filter is clogged this will have an effect on air flow, change it and see if it makes any difference, as for condenstion it is normal for they to be a puddle of water under the car if left running for 5/10 mins

[::SPG::]

Filter changed, as expected airflow increased but only when I turn the aircon on.

It still does the same thing, it is like a valve or flap is closing in front of the fan. If I increase the fan speed I can hear more noise but nothing else changes, I can hear whistling which I feel is the air escaping under pressure.

I think the reason I am getting large amounts of condensate is that I'm not getting the airflow over the evaporator and it might be freezing and then defrosting when engine off.

ANyone know the configuration of the fans and air mixing box?

[ToMBoY_C]

Sorry to gate crash, where is this filter? Mine does sorta same!

[Pit Dweller]

The cause is a faulty temp sensor located in the heater box. Common fault on the early 3C Passats.

[::SPG::]

Tomboy - very easy, passanger footwell, flexible foam type trim with 2 'thumb screws' remove the 2 screws and peel back foam. Slide cover to unlock lid. Remove filter. Very easy.

Pit Dweller, is it a recall/warranty? I guess not, easy to do? Thanks for the info.

[Pit Dweller]

Yep, very simply to do. Take off the centre console side trim on the drivers side (You need a size 20 torx screw driver to remove the screw next to the clutch pedal, pull the trim down when the screw is removed) At the bottom of the heaterbox facing diagnally out towards you, you will see a 2pin black connector connected to the temp sensor, unclip the connector and then turn the temp sensor 90` to remove it. The sensor should be a short stumpy one. The new one is about 4 times as long. Fit it. Refit trim. Job done.

[::SPG::]

thanks Pit Dweller, almost doesn't sound worth having an arguement with VW about (I brought it approved from them 6 months ago, notice the A/C was weird 3 months ago but didn't do anything)

[Pit Dweller]

You got a warranty on the car?

[::SPG::]

Yes, approved VW but it is limited (some we say very) and doesn't mention the AC systems at all. If it has been sooner I would have felt better arguing it.

I want them to check the front bushes too, very creaky and I know that was an issue and is covered by the warranty

[Pit Dweller]

OK - Will have a look for the part number of the sensor you need tomorrow, if it's not covered by the warranty it's no big issue to replace yourself.

[DSG4ME]

The aircon is sensor driven, it automatically adjusts the temp and fan flow to obtain the desired temp, so you can in fact want it warmer and have it nice, then someone lets cold air in and the car will raise the temp up until it gets to the temp on the dial in the car again.

If you want to overide it, turn off the eco and auto modes, then it will constantly blow the set temp at you, but you will have the compressor working in the background using more fuel, hth.