My '92 civic has a similar problem and I've traced it to the HVAC unit itself.

I can actually press hard on the face of the unit right below the recirculate/fresh air buttons (or on one of them) and it will work without fail- sometimes it will then stay on while others you have to keep pressing on that spot.

I thought it was a relay issue at first and then the a/c button itself but nope. When it's real hot outside is when you normally have to keep pressure on it but it's random, sometimes in the cold it won't work either.

I believe it's either loose connectors or, more likely, that the solder joints have cracks in them. Similar to what causes the main/fuel relay to act up on our cars. I haven't gotten around to taking it apart yet but I'll buy a soldering iron and do the work myself before I pay $300 for a new unit.

The "press-location" most likely wouldn't apply to your accord but I wouldn't be surprised if it was the same issue - just throwing it out there.

 

just put a hot solder gun on the connections and all ur cracks will be taken care of.

 

i think i have a similar problem on my 95 accord. i connected the compressor's power line straight to the battery and my a/c started blowing cold air. could someone post a diagram of where the a/c relay is located? thanks.

 

its on the driver side bolt of the driver side fan on teh radiator. there're two relays. one is the compressor and one is the fan. i forgot which one is which.
but if ur a/c fan works, then a good way to test it is by switching the relays.
switch the put the compressor plug in the fan realy and viceversa.

it'll tell u if its the relay thats really bad. mine was a pain in ass. u have no idea what i didn't do to figure out what it was. at the end i gave up and took it to an electrician and all he did was jumped two wires coming out of the ecu. and charged my 110 bucks (thats why i didnt wanna go there in the first place)

but later on i replaced my ecu and removed teh jumper and it worked fine.

few months later the thin circuit wires on the chip board of a/c control unit blew up.
i fixed those by rewiring them. its been working fine since, been more than an year already.

and by the way, my relays were blown too.

 

Update on intermittent AC cooling. I finally got my hands on the car again to do some troubleshooting. When it's working the air is cold so I'm not sure how it could be a low refrigerant problem. When AC is blowing hot air the condensor fan is still running but the compressor is not turning. So, something is causing the compressor to not run when it should. From my research on this it seems the fact that the compressor is not running when the condensor fan is running should rule out a problem with the AC switch. I think, but am not certain that it should also rule out a thermostat (in evaporator) problem. I'm not sure if it rules out a possible pressure switch problem. Does anyone know if the condensor fan should run when the the compressor is off due to a pressure problem? Also will a low pressure (like low refrigerant) reading cause the compressor not to run just like a too high pressure? I'm leaning toward a bad compressor clutch relay being the problem. Do those fail intermittently, as opposed to solid failure? Thanks.

 

Update: I checked the refrigerant level & pressure & it is fine. One more Q&A & I should have this figured out. If my pressure switch is bad, would the condensor fan run & the compressor not run? Does the system need to be evacuated to replace the pressure switch? If the condensor fan should not be running if the compressor is not running then my next step is to replace the compressor clutch relay which has been my chief suspect all along. Appreciate any knowledgeable feedback out there. Thanks.

 

Update: I checked the red clutch/coil lead in "failed" mode & I still had battery voltage which proves my relay is fine. I then forced the clutch against the rotating pressure plate (exciting - I recommend a thin wooden stick/pole - less sparks than metal) & lo & behold, it engaged. The gap is out of spec - not by a huge amount but it is bigger than the outside tolerance. I guess that over time the natural progression is for everything to wear & loosen to a wider gap.
So, it seems clear I need to pull the clutch & remove some shims. I've never messed with a compressor clutch & there is precious little clearance from the end of the clutch to the inner fender - maybe 3/4". I'm not sure what I'm getting into here. I don't think there is enough clearance without pulling the compressor & then I'm not sure you could do it without evacuating the system? Can you do this with the compressor in place or must it be removed? I'm wondering if I might be better off to take it to a reliable mechanic & have them do this. I wouldn't expect there to be too much to it for them....maybe 1 hour labor or something like that? Any opinions or experience on this? Thanks again.

 

To whom it may concern: I'm going to close down this thread which has become a monologue anyway. I've gotten much better response & help over on the Honda Accord Forum in case anybody is interested in this topic. Thanks.