'98 Integra, 210K miles, no serious problems.

Recently, the A/C started cutting off intermittently. Usually happens
when it's particularly hot (we live in GA, so this happens often right
now) . I've checked the freon charge, and it's showing OK. I think
something's causing the clutch to disengage. A friend told me she had
a similar problem & the shop siad it was "a sensor" that was shutting
the system off. Could be, but I'm not ready (yet) to spend the $$ at
the shop to find out

Any suggestions as to what sensor & where, or fault isolation
techniques that will work on this system?

Thanks!