OK, here goes:
My car was in a front-end collision which required replacement of the A/C condenser...and naturally recharging of the system. All performed by an Audi Dealership. I was called to pick-up th car after after the completion of the repairs: body work, new radiator, condenser, inter-cooler, etc. The A/C appeared to be working fine upon immediate return of my car. However, the next morning my A/C is no longer blowing cold. No faults, no ECON light, nothing. So, I press ECON off and on a few times to see if anything happens...NOTHING. So, I leave it in ECON mode for a bit...but about 15 minutes later the heat is getting to me so I turn off ECON mode...and now the A/C is working. I conitue my drive to work, get back in the car at lunch...A/C is still working. I get in my car 3-4 hours later to drive home...the A/C is still working. So, I'm thinking OK, that is weird. I park the car overnight, get in the next morning...A/C is NOT working!!! I fiddle with the ECON button...again NOTHING. So, I turn ECON ON and drive to about the same spot I was the day prior...at freeway speed (60mph)...turn ECON off...the A/C begins to work again!!! Like the day before, it worked at lunch (about 4 hours later) and it worked on my drive home (about another 4 hours later). So, over the next few days (actually weeks) I noticed a 100% perdicable pattern as described below:
1) During all of this time, there have been no codes which can be read by VAG-COM.
2) If the car has been sitting for more than 6-8 hours, the A/C does not work until the following two conditions are met:
a) The engine must be a full operating temperature.
b) The engine RPM must be at a sustained RPM above 2,500-3,000 (60-70mph)...for initial engagement only.
3) If I am doing low RPM city driving, short burst of RPM, the A/C will not engage...even if the engine is at temperature. Also, If I drive to the nearest freeway where I can acheive a sustained RPM, if the engine has not been to temperature for a while, the A/C will not work for another 10-15 minutes...even at sustained speed.
So, it is VERY temperature/RPM related. However, once you meet these conditons it will work fine. Even if you stop at a stop sign, do city driving, whatever. Once it begins to work cruising above 2,500 RPM...it works normal until the car sits for 6-8 hours. Then the process must be repeated. This has been going on daily for about 2-3 months...with car being driven daily. Again it is 100% repeatable and predictable. But what the heck is causing this.
Any ideas? Again, I have ZERO codes in VAG-COM from any module!
Any help would be appreciated.