Hoping someone can help.... So my A/C is working....and then it's not. I will be driving and AC is working, blowing cold. I have noticed that it doesn't seem to be cycling on and off like it normally did, now it just blows cold all the time, which is fine by me. Then all of a sudden it will stop blowing cold and start blowing warm air. It sounds like the compressor kicks in, as you can hear the change in the rpm's, but I'm not getting that (hiss/pressure sound) when it starts blowing cold. If I leave it running, sometimes it starts to hiss again and starts blowing cold, other times it doesn't. Sometimes if I shut the air off for a bit then turn it back on again, it'll start working. I checked the freon charge, and that's good. I also just replaced the 3 relays under the drivers side headlight that control the AC yesterday in hopes that would fix it, but it didn't. Any help would be appreciated.

 

You said you check the freon charge.. are you checking with manifold gauge set? If so what pressures are you seeing?

 

Marc, my hunch would be that one of the following sensors is intermittently failing:
1) AC Pressure Switch pg # 21-38
2) Evaporator Temp Sensor pg # 21-43

If you are into doing some troubleshooting you can determine if these sensors are working properly. If so, download the 09-12 Honda Fit service manual from the sticky called "Factory Shop Manuals". I put the page # next to eachsensor. The service manual is very detailed, even so I would try as many steps as I could. And I would start with the AC Press Switch first because removing the evaporator looks complicated.

 

I know very little about working on cars to be honest. I went and picked up a freon recharge kit just to use the gauge on it to check the levels and it did not need a recharge. It is blowing out icy cold when it is working. I would assume if there wasn't enough freon it wouldn't blow cold at all. I'm thinking it's some sort of pressure switch? I have no idea how many of them there are or where they're located. I'm was hoping that's all it is. I was trying to avoid the mechanic if I could to avoid the hassle of having to leave my car etc.

 

These cars have very weak A/C systems.. just a tiny bit of r134 missing can cause cooling issues.

You need to have a manifold gauge set to determine what kinds of pressures the high and low sides are seeing and a basic thermometer to check vent temperatures.. (Vent output temps should be close to 40* F anything higher than 50* F means it is not cooling properly)

This is the first step into diagnosing the issues the car is having before going further like checking pressure / temperature switches. If you don't have the experience or knowledge to troubleshoot the issue you're going to have to take it to someone who does.

The gauge that is on the the r134 recharge kit is useless and will tell you nothing but bad information.

If the car is blowing cold, then stops.. it can mean a lot of things. If your car is low on r134 it can still blow cold then stop blowing cold.

You need to read the pressures on the low and high sides first before you do anything else.

If not take it to a trusted shop to have them evacuate the system, check if its holding a vacuum and then recharge the system to the proper amount.

 

Background: 2012 Fit Base MT, 120k miles. The A/C had been getting progressively weaker each summer, i.e., one summer would get overwhelmed at 95F and sunny, next summer 90F and sunny, then 85F and sunny, etc. It would blow fine, but the temp coming out was increasingly warm ... the thing was freezing over, I think. Reputable indep. garage #1 found no issues and sent me away. Smaller reputable indep. garage found coolant leak. Added refrigerant and that improved things.

Recent 4h trip in ~85F weather: instead of the air getting less cool over time as it froze up, I found that the air speed out of the vents decreased to a trickle, even on max speed of 4! It was still cool, if not cold, but I'd never previously experienced any change in blower speed. Turned off A/C and opened car windows for 10 min. Then, rest stop for 10 min (notice drips under car). Resume highway trip for 10 min with windows down, then turned on A/C, it blew strong and cold again.

On return trip, used A/C mostly for defogging in heavy rain. BIG puddle in garage upon return home ... enough that occurred after car was off to indicate melting of ice, beyond the amt of water that I think would be normal and only during actual operation.

Any idea what might cause a temporary but sharp decrease in blower speed if the switch hasn't been moved off of "4"?

Also, if there's a leak in the system, can that be fixed without a >$1000 replacement A/C system? Should I go for a tint job and a second recharge first?

 

If I can add to this thread, I'm having a similar issue with my 2013 Honda Fit LX. I'm only noticing issues with the AC cool during road trips that exceed approx 2 hours in length. I will have the AC set at a fan speed of 3 (or more), and the temperature set to the lowest setting (recirculating air). At about the 2-hour mark, my car fan starts sounding like this, and then the fan makes the noise in the video attached, and the cooling performance goes down significantly.

https://photos.app.goo.gl/VmrFKQ68E57ZYZR49


If I leave the car off for around 30 mins, the AC goes back to normal.

I've also observed that if I leave the fan speed on a #2 during a road trip, this problem does not re-occur (my current workaround).

My dealer was unable to replicate the issue, so we have proactively changed the fan resistor 79335-TF0-G01 and the fan motor 79310-TF0-G01 without success (the only difference is the air got a little colder once the issue started re-occurring compared to not replacing these parts)

 

JoeNewman1981: I could not tell much sound-wise from your video. How would you describe the change in words? Was there a grinding sound?

As for my case, I put a digital meat thermometer in the vent and noted the temps of the recirculated cooled air varied between 35F and 45F. I guess the compressor was going on/off, and it's my understanding that that's normal. Probably going to have my guy look at it Friday. He last added refrigerant 8/9/22, so it made it almost a year. It's quite hot now where I live - mid 90s all week. Last week when this thing acted up after a 2 hours of driving, it was probably mid 80s.

Oh, I did check the filters. Turns out I had let my cabin air filter go longer than I planned. Usually I change it annually, 12k or so. It had been 18k! [Must have been distracted by an even older Honda we took in during that period]. But I don't think the extra stuff in the filter was the cause of the problem, because the strong A/C and strong blowing came back after giving it a 30 minute rest (melt). But maybe a clean filter would have helped it get a few more minutes/miles down the road before that happened.

Nevertheless, I did change both the cabin and engine filter today. The engine filter hadn't quite gone 12k, but it was quite a bit dirtier than I'm used to seeing for <12k driving. Usually, it outlasts the cabin air filter. My wife keeps her car's cabin air on recirculate almost all the time, and she (understandably) gets quite a bit more life out of her cabin air filter.

 

JoeNewman1981: I could not tell much sound-wise from your video. How would you describe the change in words? Was there a grinding sound?

Sorry if the audio wasn't great, but I suppose I could equate it to a higher pitch, almost like a whistle, but it simultaneously lost a significant amount of airflow, even on the highest setting.

 

Intermittent A/C issues could be due to the A/C clutch, see: https://www.fitfreak.net/forums/2nd-...-c-clutch.html

 

Intermittent AC may be caused by the pressure cutoff switch on the high pressure line attached to the side of the radiator shroud. It collects dirt due to pointing up wards with gravity letting dirt settle eventually in the connector. Use brakeclean to clean it out and electric grease (silicone) to protect the connectors and put some on the outside of the connector to seal the connection. Your welcome. Clay