2010 Honda Civic A/C Works Intermittently?

I have a 2010 Honda Civic and my A/C works intermittently. It usually only stops working when it is extremely hot outside. In the past it has kicked back on after driving for a while, but recently it hasn't been doing that. It will only come back on when the car has sat for a couple of hours. I thought it was the relay and replaced that, but that did not work. Has anyone else had similar problems? Does anyone know what the issue might be?

When the car gets too hot for the AC to run, open the windows and flush out the hot air. That will get it back working faster than sitting in the sun all closed up.

If the blower is running but no cold air comes out, the ac may be blocked with ice. Open the windows and run the fan only until the ice melts.

Many possibilities… A couple: if the refrigerant charge is a bit low, a pressure sensor may shut off the compressory to keep it from "burning out"… Or, the evaporator could tend to ice-up. Have a competent auto AC tech check it over - you want to catch any problem before the compressor is damaged (since the refrigerant carries the lubricant, a low charge can cause excessive wear). BUT - at 9 years old it wouldn't be unusual for it to need a major repair, like a new compressor (just had mine replaced on a 12 year old model with 70,000 miles: total bill $725 at independent shop - dealer wanted $1200 for the part alone).

You didn't say Anything about the FANS. They are Critical to AC operation. One Fan should come on whenever the AC is on. The other Fan should come on when the engine is slightly above normal. They have Relays too. Check to see that they both work when they should. On a really hot day one fan should keep running even with the engine off. It will shut off when the engine reaches a lower temperature. There should be a Warning Sticker on the Fan Shroud saying the fans can come on at any time.

I check the condenser

A trained person, who understands refrigeration principles, electrical circuits and has a gauge set to measure the LOW and HIGH side pressures of the system can do some initial diagnosis and then tell you something.

Nothing less will be satisfactory.