AC problem with 2010 Honda civic

[Mike Renna]

We have a 2010 Civic LX 4 door sedan.  Works great.  But just this weekend, the AC was on and it was blowing cold.  My wife says she changed the blower speed and it started blowing warm air (bad coincidence?).

I know enough to be dangerous.  And we have a 2013 Civic with working AC but there's interesting differences.

Wonder if people can give advice if I can fix it or if it's a big expense, my wife wants to sell it.

Looking in fuse / relay box on both units, the 2010 has a relay with snowflake and rectangle and another relay with just the snowflake.  The 2013 has just 1 relay with a snowflake.

When we engage the AC on the 2010, the 2nd radiator fan does kick in but the center of the compressor does NOT start spinning

I think I checked each fuse on under engine and by driver door fuse boxes.  all look OK (and that the fan turns on - does compressor and fan get fed from same fuse?)

I swapped relays between cars and problem stays with the 2010.  (again, is the relay controlling fan AND compressor?)

It's been blowing cold fine / it was a quick change to warm - so not a slow leak of freon.  No, we didn't go over a big bump / run over something that might have damaged freon lines.

There's no sight glass for freon like in the old days, right?

I tried measuring voltages of a connnector above the pressure switch on 2010 (doesn't seem to have a pressure switch on the 2013?) and on a connector leading down to the compressor.

The connector leading down to the compressor has 1 of 3 leads that's hot even with the car off (not switched by the AC as I would think).  That seemed to be the case on both cars.

I have read different things - if it's a low pressure issue, the switch / sensor keeps the compressor AND fan from running (so the fan runs means freon is ok?).  Others say otherwise.

Any thoughts?

Gambling is legal in all states - would you bet it's the compressor that needs to be replaced?  Low freon?  bad pressure switch?  Something else?  

THANKS!

[Gusmanlee]

Hi Mike. I'm resurrecting this old post, as my son is having the exact issue with his 2010 Civic. All the symptoms are exactly the same, as are the steps I took to diagnose the problem. I did use a AC manifold gage, and the system is still full of freon. Did you ever figure out what the issue was, and what was the fix? Thanks.