2002 A6 2.7T

I recently had my auxillary water pump replaced due to a severe leak of coolant. Now it seems that when I turn the temp up in the cabin the fan indicator ramps up like it is going to full power but no heat blows into the cabin through the main vents. It does seem to blow out at the bottom and front windshield, but not very much. Interesting thing is, it's set to AUTO and when I go faster the cabin does warm up. But when I slow down it gets cold and never maintains the heat. Strange! Anyone have any ideas as to what this might be?

 

heater core going bad? Found any water on the passenger floor? Your thermostat might be stuck open.

 

I think I may know now after further investigation. I am getting heat on top of dash for windshield and I get heat on bottom floor, just not out the main vents. Possibly blower motor died?

 

What concerns me about your post, is that you stated it is only heating up when you are accelerating. Is it still doing this, or is the problem only with the vent now?? I had a similar problem. We had the water pump replaced, and the heat was still an issue as was the coolant. Later it was because the thermostat was stuck open. I still wouldn't rule that out. The water pump, timing belt and thermostat are recommended to be changed at the same service. Usually the 70-80k mark. I'm not audi specialist though, so I would keep searching for answers. Hope this helps!