'95 Civic--intermittent A/C cooling problem

I have a 1995 Honda Civic with only 80,000 miles on it.

There's a mysterious intermittent cooling problem that two mechanics 
have so far failed to fix:  The A/C just stops cooling after 15 minutes 
or so.  If I cycle the A/C off and on with the dashboard controls a few 
times, it seems to engage and start cooling again--only to stop cooling 
some time later.

So far, my mechanics have found that the clutch isn't engaging for some 
reason.  They suspect an electrical problem of some kind.  They have 
checked the refrigerant level, the compressor, the clutch, and the 
clutch relay.  The clutch relay was just replaced.  But the problem 
persists.

My mechanics have been reduced to a fi****ng expedition--keep replacing 
different parts.  They don't know any other way to find the problem.

Any ideas what else could be causing this?
Any way to track down the problem systematically?
How many switches and relays are involved in a Honda Civic?
Could it be a sensor of some kind?

Any advice would be most welcome!


-- 
Steven L.
Email:  sdlitvin@[EMAIL PROTECTED]
 the NOSPAM before replying to me.