IcemanG17

Okay heres another problem I have on my 88 S4 auto. When you slide the climate control selector to the "feet" position, no air comes out at your feet. The defrost and vent work fine. I'm thinking a vaccum leak/acutator problem?

Another thing I noticed & didn't know if its normal, is that when driving in cool temperatures (say outside air 65) and I have the climate control set to 65 with the "vent" on, (but not the A/C) the air that comes out of the vent is fairly warm, much warmer than the outside air. If I turn on the A/C it gets cold no problem, but as soon as the A/C turns off it gets warm again? Is this normal?

UKKid35

Excellent help on the HVAC is available here http://members.rennlist.com/pirtle/svc.html

Rich9928p

You need to test the vacuum circuits to determine if there is a leak in the actuator (pretty likely).

There are two causes of warm(er) air during vent. The dash is packed tight with many electrical items that are warm and heat is transferred to the cooler vent air so that heats up. The second (and most likely) is your heater valve is not closing and hot water is circulating in the heater core and is heating up the vent air.

If you have weak vacuum due to a leak in an actuator, you may not have enough system vacuum to operate all of the other vacuum motors. It isn't a bad idea to replace the heater valve every 4 - 5 years as a maintenance item (every other flush).

IcemanG17

I'm thinking about checking the actuator and vaccum lines 1st, that should fix my original no-feet problem. It might fix the warm air vent problem too? If it doesn't then I'll check the heater valve!
Thanks