I had our a/c overhauled this March with a new compressor and refilled with Freeze12 on 1992 745. I have been very happy with the results so far, blew very cold up until yesterday. We had driven about 45 miles with cold air, then turned off the car and went into a mall. When we came back out it was raining so turned on the defrost. Once the windows cleared turned the (manual) switch back to dash vents. Air was no longer cold, just outside temp air. Stopped by my mechanic who did the a/c work and as would figure he is out on vacation until next week. There was no visible evidence of having lost any of the coolant. I checked the fuses under the ash tray and have not found any blown. The car is not overheating. I checked the FAQ but have not found a similar problem. Any ideas where to look next?