95 Civic, weird A/C problem

I have an old '95 Honda Civic with the following bizarre A/C problem:

On hot days, the A/C blows nice cold air, no problem.

But on mild days when it's just a little warm outside, the air coming
from the A/C keeps fluctuating in temperature: It's cold, then a few
minutes later it's warm like the A/C stopped working. Then some time
later the air gets cold again. I think (though I'm not 100% sure) that
if I cycle the A/C recirc buttons on the dash back and forth, turning
the recirc on and off, that seems to trick the A/C into blowing cold air
again.

I thought it might be the thermostat, but the mechanic says it's working
fine.

Any other causes you can think of?

 

It's probably the compressor turning on and off as it's supposed to.
You shouldn't use the Air conditioning on those days.
Bg

 

Thanks for your help.
However, I just got a phone call from my mechanic. It looks like the
problem is the compressor clutch. That's going to cost me.

 

I think it's unlikely a compressor clutch would work reliably on warm days,
but not on average days, when the temp under the hood is much more dependant
on the type of engine use.

How about the AC pressure sensor for the condensor fan? On hot days, the fan
might be running anyway because of the engine temp. On not so hot days, if
the AC needs to loose the heat, but isn't triggering the fan, the pressure
could increase to the point that the high pressure cutout is stopping the
system from working.

Check that the condensor fan is running when you think the system isn't
running like it should, also the compressor clutch volts if you can, if it
isn't being engergised, it's not the problem. If it is, you could remove the
outer plate if you can get to it, and see if it has been "over shimmed".
I've seen this a few times.

If the output pipe from the condensor is hot, normally the condensor fan
should be running.


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