On the A5's with either Climatic or Climatronic the fans are directed to run by the ECU, and they do not start until the refrigerant pressure sensor calls for them to run. So some time after the clutch engages temperature will rise in the condenser, causing pressure to rise, the pressure sensor tells the ECU that pressure is rising, the ECU tells the controller on the large fan to start both fans and run at a certain rpm. Then the fans start moving.d2305 said:Radiator fans not the a/c blower. Both fans should come on when you push the a/c button.
A wild guess here so take it for what it's worth but if the car sits for a period of time the refrigerant becomes a liquid as it gets cold and looses pressure. As the refrigerant warms up the liquid is boiling into gas and is able to be pumped safely. Perhaps the delay is safety feature to protect the compressor from pumping a non compressible liquid on cold start ups.glandpuck said:I want to thank DanG144 for his generous contribution to my problem and generous gift of his time. Today, working with Dan, we hooked up the VAG-COM to my vehicle. There was an entry in the HVAC module called standing time. With the car cold from sitting overnight, this value was set to 04:00. The compressor pressures did not rise immediately with the AC turned on. The compressor pressures did rise after a couple of minutes and the fans came on and variably increased thier speeds as compressor pressure rose. Dan directed me to turn off the engine. We then waited about 3-4 minutes and re-started the vehicle. This time, the standing time value was shown as 00:00 and the compressor pressurized up quickly. Compressor pressures were up to 13.2 Nm and baseline about 9 Nm.
direct measurement from the high and low port with the engine off were 100. Low port, engine on = 100, High port engine on = 175 - 200.
Dan is further donating his time to interpret this data as the problem of "delayed Ac cooling on the A5" has been reported. As of now, one can only speculate if this is a feature of the AC system design or an abnormality.
Your 2015 is NOTHING like your 2015I know this thread is old, but, just last week my 2015 TDI Beetle started doing this same thing. I just picked it up from the VW service and they told me this was normal. It was not “normal“ until last week. Has anyone found a solution to the issue?