I have a 1995 850 turbo wagon, and I have read the discussions on various problems with the air conditioning system, but I think my problem is different.
This just started about a month ago, when driving in high altitude, the a/c just gave up and started blowing (essentially) outside air. I should mention at the time that we were occasionally opening the windows to smoke, and it just seemed like the system got overwhelmed by the humidity.
The next day, it happened again, under similar circumstances (it was also 90+ degrees F outside). But later that night, it worked fine as we drove across the state 350 miles home.
Since then, it has worked fine, until a trip on a hot, humid day again. Then, we shut it off for half an hour, and turned it on again and it worked fine (we have an automatic climate control, and we just set the fan speed on "high" rather than "auto" which seemed to help). Then, when it got too cold, I turned the fan from "high" to "auto" and the A/C gave up again immediately, though the fan continued to run. I did just recently replace the blower motor on the fan, and it is working fine.
It strikes me that - even though we are getting no codes from the system - there might be a problem with a switch or relay relating to the automatic setting, as the A/C seems to work perfectly every time I set it on high, but not on auto. Am I on the wrong track here, or is this something? South Dakota Tom