1995 Honda Civic DX A/C problem

My a/c works fine in the morning, but by afternoon the a/c won’t “click” on. If I push the “outside air” or recirculate" button really hard and hold in, I hear the compressor “click” on. But, as soon as I let go, the a/c goes off again. Two mechanics later, the problem still exists. There are no freon leaks, the schrader valves have been replaced, and the freon filled. Please help!

Did either mechanic check the High and Low pressure switches? I had a similar problem with a 2000 Blazer in 2003. One of the switches was replaced (forget which one) and the A/C has been fine since.

Ed B.