Hey guys.. my girl has a 2003 Accord EX and the A/C isn't working. The blower fans work, all the lights come on, but the air isn't cold. What steps should I go through to diagnose the problem? Should I go ahead and replace the relay as a cheap attempt? As far as I can tell, it doesn't sound like the compressor is turning on.. no change in engine sound when turning it on/off.

 

You should do some diagnostics first.

Start the engine and watch the plate in front of the a/c compressor pulley. It should not spin with the pulley. Turn on the a/c and see if that plate spins with the pulley. Also see if both fans on the radiator turn on when you turn on the a/c.

 

Thanks. Is that the left-most part of #9 / the part next to #8?

What else should I look for after that?

 

That is the correct part.

The next step depends on what you find in the first step.

 

Thanks. After I see the car today I might not be around it again until Saturday. Anything else I should look at today while I am around based on what happens with the outside plate?

 

If the plate doesn't move, then unplug the electrical connector to the compressor, then see if you get voltage to the compressor.

In the DIY section, there is a writeup on how to get HVAC codes that may help you.

 

So I was able to take a quick look yesterday. The placement of the compressor makes it hard to get a good look at that outside plate. I was able to see just the edge of it from looking at it from the top (see picture below). This particular piece didn't spin regardless of the a/c button being on or off, but I am hoping this was the part I should have been looking at. Can you confirm?

 

That is the correct part.

The next step is to figure out if you are getting power to the compressor. Just unplug the compressor and use a volt meter to see if the electrical connector to the compressor is getting power when the a/c is turned on while the engine is running.