Air Conditioning Question

[lugnuts]

When I purchased my '90 Reatta 2 years ago, the AC compressor was replaced (Delco), and the system recharged---R-12. It performed like a champ until last September when the AC warning light came on, and there was no cold air. I put the car away for the winter in November. When I took it out last week, the AC system worked fine ( plenty of cold air) and the warning light was not lit. The outside temperature was then 58 degrees. Everything was as it had been, the system worked A OK. Is the AC system showing this behavior due to the cooler outside temperature? If so, what is the cure. Does this mean the system is low on R-12? If so I suppose this means there is a leak someplace. Has any one elese experienced this same problem?

Thanks for any help offered.

[DAVES89]

Just yesterday I ran my A/C and at 69 degrees outside temp and everything was fine. When the temp dropped to 66 degrees outside the warning low coolant came on. My advice would be to reset the codes and run A/C at above 70 degrees outside temperature. At least that is what I am doing.

[Roadster90]

I think many (including self) have this same situation. Dave's suggestion above is what the majority of us do I believe. It would be nice however, if we had an A/C Guru on the board that knew exactly what was causing the situation....such as a low pressure switch, worn out compressor, or whatever .

Would also benefit some of us if someone knew exactly why or what to do in the case of the A/C blowing warm air at stop lights and working great while moving (???). I intend on getting the prom/mel cal reprogrammed to start the fans at a lower temp (GM Tuners). Not sure if a re program will resolve this problem, and it would be Great to know the real reason for the condition (???).

[Guest tomt]

September seems a little early, but I don't know where you are. The warning comes on occasionally for me in cooler temps, say when I really don't need air. At that time of year now I traditionally switch to Econ mode rather than Auto. I don't have the problem then, and am not sure why.

[lugnuts]

Perhaps, I didn't make my situation clear. In the warm weather, the AC warning light is on and there is no cold air. When I ran the system in cool weather (58 degrees)as a test, it performed OK; cold air, no warning light. It is working backwards. I wanted to know if any one else had this problem and had found a solution.

Thank you all for the input.

[D-a-n-i-e-l]

I would have it seviced before summer if you like cold air. Your issues is bacward from what should be going on if a AC system is operating in it's lower capacity area. The only thing that would make sense to me is that the low pressure sensor has a max value that it can handle. I mean when the pressure gets too hight the computer reads it as low. But I would say that this is extreemly unlikely. When you bring it to be serviced they will most likely try to switch you to 134a, If you are not compfortable with the change it may take you a minute to find a shop with R12 on hand. Also you could wait until summer hits and check the pressure yourself but I would just get it serviced now that way when your shop puts the minimum amount of charge on it you will not have the issue of low pressure issue in the fall and winter.