[lsupcar]

As a follow up to my original post, I had my system rechecked by the shop and all parameters checked out ok, and they said the next step was tearing into the dash as they were getting a code for the light sensor. I did not think that was a likely cause so did not pursue it further as the system worked ok for the most part.
I did receive a PM from a member with a similar problem, who said his problem was fixed with a new a/c control unit in the dash. I will try that if the situation worsens over the summer.
Bill