VW GTI in Shop for AC
 

OK. So my '07 GTI's AC works only after I have been driving for about 15 minutes. It comes on almost like clockwork. I drop the car off and the technician calls me around 12:30pm. He says it is hooked up to the computer and they are running tests on it. They won't know the results until the next morning.

Does it really take that long for the computer to diagnose the problem or are they too busy to really get around to my car today?

Depends.

The Snap On scanner we had allows you to perform tests in real time. However, we would often perform tests at various intervals. i.e, test it as it sits, take it for a drive, bring things up to temperature, test again, test after it sits for a prolonged period of time, etc.

If they're implying that they're waiting for their scanner to actually compute its findings, they're probably full of shit.