My daughter just bought a 09 sport with 79,000 miles on it.

The AC blows, but it is not cooling. The clutch on the compressor does not engage.

I have checked the, compressor, switch on the dash and the relay.
If I give it power at the compressor the clutch engages and I have cold air.

Any idea of what else to try?

 

South Main Auto just had a video diagnosing a similar issue on a truck, might give you some ideas:

 

Do the radiator fans cycle on and off when you have the AC on? If so I had this exact scenario not two months ago. Power at compressor would create cold air. There's a trio of relays behind the driver's headlight, in a little box that you can get into without tools. In there, replace the compressor relay with a 39794-SDA-A05 (Honda relay part number, Mitsuba brand I think)

It'll fire right up, and save yourself about $110 bucks (ask me how I know... )


EDIT: For shits and giggles for anyone who finds this thread in the future here's a link to where to buy compressor parts for cheap. I got quoted 1300 for a full system replace!

 

I tested the relay and it shows good.
I then swapped them and it still isn't working...

 

Thanks for the link!! that's awesome!

 

So I found the issue...

The PCM is bad. There was wire damage due to rodent damage. The previous owner covered the wires. It shorted out one of the modules in the PCM.

I can get a used PCM for ~$75. My question is can I swap it out and have my Fit work? Does it need to be reprogrammed or can I just swap them?

 

Possible pressure switch? Maybe seeing too low in pressure?

 

Yikes! What year model is your car? 2009 MT / AT? If its not the PCM/ECU but the wires? You may just need a new/used wire / harness.

 

I think I'd try a straight swap BUT you have stuff to consider. I spoke with Mr.Manuel, and he said that if you're replacing the ECM you'll need to change engine and tranny oil and clean the throttle body so that when the computer gets programmed to the vehicle it starts with a relatively clean slate and it's service intervals can be accurate-ish (I read between the lines for that bit). In fact, besides the physical stuff there's a bunch of stupid computer stuff you may need a Honda diagnostic tool for. The injection system has to be "inspected" electronically, and.. the throttle position.. The transmission. sh*t the immobilizer may deadline your car after install and you'll hafta pop in the old one n cart it over to honda (unless free towing is an insurance perk you enjoy) I'll upload Manuel's instructions.

This is the real reason why we hate rodents. Someone needs to start making wire jackets that taste like .. I cant think of anything that someone, somewhere, wouldn't put in their mouth..
Anyways yer looking at a cuss-load of handheld computer fiddling. With the immobilizer in mind you might not have a choice. Talk to a service writer type and see if they're cool with you prepping it for surgery yourself.

Sorry this is where yuh wound up.

 

I took it to a auto electric place. I fixed the wires and they tested fine. The PCM shows a bad module in their testing. The can get the signal calling for the AC, and they can send voltage through the wire and get the AC to work, so they are confident it needs a new PCM.

 

Thanks. I'll take a look at they manual stuff.

 

How do I tell if its MT OR AT?

 

I think you know, but maybe the acronyms are throwing you off. Manual transmission {MT} or Automatic Transmission {AT}. Just in case, do you have to manually shift while driving, or do yuh just press the gas pedal to go?

Moving on, there's a fuse you're supposed to check before replacing the PCM. I'll send this asap then look up the fuse. don't buy a darned thing yet

EDIT: Kay, I got files for you to read. The fuse you *must* inspect is #43.
The fuse box is to the lower left of the steering wheel. bring a flashlight just in case. There's two little doors for you to remove.