Air Con Issue

I have a problem with the climate control in our '05 A3 Sportback. When you switch on the air con in any mode (auto or manual) the fan comes on as normal then after about a minute the air supply to the vents shuts off. The fan stays running at max speed but the air flow from the vents is negligible. As soon as you hit the Econ button air flow through the vents returns. If I increase the temp in Auto mode vents will open eventually also. I have concluded that if the compressor is running then the air supply to the car is being shut off. Why? Removed pollen filter last night but no change! Any Ideas?

Don't worry. The 'auto' function will mix outside and recirc air. The 'eco' function only brings outside air in. All is ment to maintain the cabin temp to the setting you chose. It is a fully automated flap/airvent control.

Thanks Godfried, Any idea what is causing our problem. As in Auto mode we get no air at all from the vents. When I hit econ then air comes from the vents though obviously not cooled. Raising the temp can alsoallow air flow, depending on the outside temp. Basically I think that as soon as the compreesor starts going off air flow through the vents starts again.

Set aircon at lowest (coldest) value on auto. You should get a result there. If not, better let it checked.

At lowest setting then vents close completely i.e no air out. See earlier posts, when compressor is on air flow through vents reduces even though fan is running at max speed. The more cold air you ask for the less air flow through the vents. When you hit econ (which turns off the compressor) then air flow returns. Was hoping to get some tech help here so I could repair myself. Car is out of warranty.

Don't know now. You might need a re-charge. Sometimes you can lose up to 30% freon a year. Also, matters such as clogged filter/dryers, expansion valves and faulty compressors might cause the problem. Silly perhaps, but check fuses. Hope it is something simple and minor.

Thanks again, checked the Gas pressures, All OK there. Compressor is also functioning fine. Fuses also ok, removed filter earlier on, dirty but not problem either. The more time spend at it the more I am convinced that whatever mechanism opens to allow cooled air through the vent system is my problem. This must be in the air box somewhere, question is where and how does it operate? how is it controlled?

I had a problem once with the automated flaps of the aircon (different car make) they are all controlled by little electric motors, a bit like scalectrics. I had to open some with a screwdriver. I let them in that position. Continuous air flow, but better than no cool air at all.