2nd Gen Non-Engine/Transmission A/C Temp. Switch

[JRS]

I have an intermittent problem, probably the hardest kind to find. While cruising down the highway, with the A/C on and the temp. switch at the 10:00 position, the A/C will quit cycling. It doesn't happen right away, but after about an hour of use. If I put the temp. switch warmer or colder, the A/C starts cycling again. It only happens in this position. Any ideas?