Hi, My Aircon Blows more hot air than cool air and it certainly never blows cold air.  Ive had it Recharged twice in as many months, It does not leak gas yet it still will not blow cold air.   At best it blows Ambient temperature air but more often the air it blows is warmer than the outside air temperature.  No matter if its set on the Blue LED setting or 18C 19C settings it blows warm.    Ive had it checked and the Diagnostics pointed to a faulty A/C pressure sensor which was showing 5025.20 bar instead of 7.5 bar...so we changed that switch, so far this has cost around £200 for recharges , labour and a switch. 

 

Yet it is no better for it, why would it want to blow Hot air when it's set for Cold, is there some other sensor in the cabin that wrongly makes it think that it should be hot air In the cab rather than the cold air I crave?

 

I was looking at the Compressor to see if owt happens when the Aircon is switched on, I expected to see what I believe to be the AC clutch  head inwards towards the compressor to engage the compressor itself, it didnt, it still stayed about 7mm off the flat of the compressor pulley. maybe it doesnt work like i thought and engages in some other way.

 

The Cars a 2008 2 lt 140 PD Elegance.    It's had a fault warning which ive mentioned in here before for the Cornering Headlights. Im just wondering if all these Issues are somehow related to each other.  Is there an ECU that can go wonky?

 

Please help, Im at my wits end with this car this summer, It'll be worse in the winter when I cant clear the Condensation from inside the car with the AC on...

 

Im tempted tp get rid of it....But..Its a lovely car AC besides.

Edited 26 August, 201312 yr by blood

Your car doesn't have a compressor clutch as such, it's always engaged.  There is an internal solenoid that vibrates, moving a swash plate that can vary the displacement of the compressor pump from around 2% to 100%.  This is how the output is controlled.

 

In terms of temperature sensors, there are a bunch of them.  The cabin temperature is measured by the little shiny black dot in the AC control panel under the radio.  There are sensors in each face vent and foot vent pipe on each site to measure the mixed air temperatures that are being output.  There is also an outside temperature sensor behind the front bumper.  The sunlight sensor in the forward part of the dash also contributes to the air output temperature.

 

As to what is casing your problem, I'm sorry I don't know.  I'd start with a mixing box servo adaptation.  This is a process that moves each vent flap servo through its full extents to measure how far the flap moves and learn what the end points are.  In the old HVAC control (the three-knob one), you used to do this by holding in ECON (or AC) and pressing the "face" vent button but with the new control I'm not sure if the key combination is the same.  You might need VCDS to do that.  Try it and see, you'll hear the servos all moving and the air distribution will move through all the possible combinations.

 

Then, using VCDS I'd be checking the measuring blocks in the HVAC controller to make sure the readings are plausible.  Things like, does the temperature readings of the vent and cabin sensor seem reasonable?  If it feels like 20 degrees in the cabin, does the sensor read around there? Again, there used to be a diagnostics mode on the old controller to show all the sensor readings but the new one is very different so it might be VCDS again.

 

Failing that, I'm afraid I really don't know and you'll probably need a competent dealer or auto electrician to sort it.

Mine is the same...booked in at Skoda on Monday for them to sort it out whilst it is still under warranty.  I have read of other VAG cars having the same problem with a particular type of compressor and it is the compressor that is faulty.

 

Mine takes ages to get cold (half hour sometimes) and is dependent on the engine speed...ie on the motorway at higher engine speeds it will get colder quicker (not much quicker though).  I am qualified to work on AC systems and have done so on many Aircraft sytems - which are the same as a car but bigger - no faults recoreded on VCDS, so in my humble opinion it sounds like my compressor has a fault.

 

Google VAG air con faults and have a read...quite interesting - if you like that sort of thing!

 

Gaz

Ask the garage that wrongly diagnosed the sensor for £200 off the price of the job to replace the compressor.

Hi all. I'm new to this forum. Can anyone tell me please the size of the hex nut which holds the A/C clutch plate on please. My clutch plate has fallen off and I need to find the right size one.

Thanks guys.