Hey y'all. I originally was posting to the FitFreak forums, but no one has responded. I'm also a new member, so hello!

Our 2009 Honda Fit Sport's A/C went out and I've been tracking it down. Vents blow strong, but hot. A/C compressor does not engage on any setting. Radiator fan does not engage when A/C is switched on.



Here's my post on FitFreaks. In summary, here's what I've done:

1. Checked all three relays (Radiator Fan, A/C Condenser, and A/C Clutch). All are good.
- No relays click when I have my wife turn it on inside the cabin.
2. I was able to get the A/C Condenser Fan and the Compressor to engage by bypassing the relays, touching one of the terminal slots in the relay ports with a test light (this was on accident at first, then decided to use it to test further). I do not know if the fan turned on when I bypassed the Compressor Clutch relay or vise-versa.
3. I was also able to get the Compressor to engage by using a jumper wire to bypass the Compressor switch.
4. Tested A/C Pressure Switch for battery voltage - only saw 8.8v.
5. Tested Terminal 21 in fuse/relay box connector A - only saw 8.8v.

Attached are images from the service manual detailing the steps I performed. I have not yet checked refrigerant levels - I will be grabbing a gauge tomorrow. Is the pictured chart a reliable one to go off of?













I'm really looking for confirmation from someone smarter / more experienced than myself. A new MICU is ~$700. Cheaper if I go to a junk yard, I suppose. But, living in Seattle, WA, the nearest junk yard is super far away. Heck, we can't even buy refrigerant... If the gauge tells me tomorrow that refrigerant is wrong, I'll look into that and order some refrigerant to do a recharge. Quote I got for diagnosing A/C issue was $500... I would love to be able to fix this myself if possible. Even if it is the MICU, I'd rather do it and tow it to a dealership to get it flashed so it works - would still be cheaper than servicing, I'm sure.

Thoughts?

 

First thing to check is for the proper charge. This can only be done by weighing it.

Once you have confirmed the proper charge, then go through troubleshooting steps.

 

Weighing what?

 

The refrigerant charge.

Modern systems are tiny. Usually a pound or less. So if you lose as little as 3 ounces, the system will shut down.

 

I'm going to change the pressure switch just in case I didn't get the reading right. Then I'll take it for a charge to a shop.

 

Hah! Welp, I was unable to get the A/C Pressure Switch (part number 80440-SS0-901) out. Instead, the receiver pipe (part number 80341-TF0-G01) sheared off at the connection. So, looks like I'm getting a new one of those... I'm thinking I'll grab a new thermal protector (part number 38913-RP3-A01) as well.

 

When you get the new hose installed, make sure it holds a vacuum. It could have been a micro fracture where it sheared off and was already leaking refrigerant.

The system needs a proper charge level to initiate the clutch/ac fan, if there's not enough gas in the system, it wont turn on.

If the clutch is spinning but no cold air, rev the engine up, does the AC start to blow cold when at higher RPMs? you have a bad compressor unable to get the gas up to high enough pressure for the expansion valve to open at a normal idle RPM. High side I believe has to reach 140psi before the expansion valve opens up. If you look at your pressure table, it's from 135-300psi on the high side

Since you already engaged manually bypassing ac clutch/acfan, you know those devices work.

And for all these tests, you should have a gauge manifold handy to see how it tries to compress the gas on the highside.

 

I'll probably charge myself, using the table that I showed above. And I'll get one with UV dye.

I'll attempt that once I get it charged.

I have a manifold gauge borrowed from the parts store. I've been watching videos on how to do A/C stuff.

I may end up taking it in to a shop once I get the new receiver line installed, but that would be ~$1,500. >.<

 

This only takes time. The only time I go to a mechanic shop is yo evacuate the ac lines. It costs 50$ at pep Boys. Having them charge it up is another 200$, I don't bother doing the charge with them, when it costs me only 30$ in two little cans of 134a gas.

I only need the uv dye, uv light, vacuum, vacuum oil, gauge set, valve replacements, valve replacement tool (the kind for replacing the valves in a pressurized system. And that's it.

The most expensive tool is the vacuum and Guage set. All in all, the cost for all those tools is under 600$, and supplies are about 50$. I have plenty of time, and I have a 2nd and 3rd car just in case. (work truck, family minivan, along with my 2door civic). YMMV


Evacuation and recovery tools cost $600+ and an all in one tool costs about 1,700 to start... And an awesome evacuation and pressurizing with filtration system is about 6k. I rather pay someone 50$ to evacuate my system, saves space and money.