2012 Fit Air Conditioning Blows Warm on Long Trips
 

First of all, my apologies for starting a new thread for a problem that it appears has been addressed several times with Fits going back to 2009. My reason for doing this is that having read all of those threads there seems to be no consensus as to the root cause of what appears to a widespread problem with Honda Fit a/c. Perhaps via this thread the fix will now present itself.

My story: I own a 2012 Fit Sport w/43K miles on it. Bought it brand new. Great car, yeah I know the mileage isn[t the greatest, but I love the car. No issues since I bought it except one: the a/c on long trips. I take one road trip a year, from LA to Las Vegas. The Fit has been on 5 of these trips. First two, no problem. Last 3, both going to Las Vegas and coming back, the same problem occurs about 60 - 90 minutes into the drive: the air gradually warms to the point it is no longer cool. Doesn't matter the traffic or outside air temp. I start out nice and cold and by the 60/90 minute mark I begin sweating and that continues for the rest of the trip. If I stop and have lunch, which I don't like to do, the car a/c is cold when I resume my trip but then it heats up again.

Numerous solutions have been listed on this forum:

• Cabin filter is dirty, needs replacing (I do this before every trip, it does nothing)
• Low refrigerant
• Defective evaporator thermistor
• Defective expansion valve
• Defective a/c relay in engine compartment
• Damaged condenser fins
• Defective compressor

My question is this: has anyone found the smoking gun that indicates which of these possible problems is the actual cause of the warm air on long trips air conditioning issue? It seems to me that given the commonality of the problem there should be one cause as opposed to so many possible causes.


Also, I have had my mechanic check the a/c on my Fit for the last two years after my road trips to Las Vegas and he said there are no leaks, it is full with freon and everything seems to be working properly. He asked me if the forums had any suggestions so that's why I'm here.


Sorry for the lengthy post but hopefully with some help we can put this issue with the Fit's a/c to final rest.


Bill

Mine blows warm all the time.

Always has.

Yet another reason I can't stand my car.

I know this isn't a solution, but a practical workaround I've found is to keep the temperature dial 2-4 clicks warmer than the coldest setting. Of course, YMMV. Hope it helps!

I run it at 3 instead of 4 (full blast).

Been like that since the car was new. Thankfully, I'm in a climate that's hot but not humid. I feel bad for the rest of you guys out east who have to put up with living in a swamp.

If it never cools down, then it's probably an A/C charge issue. The compressor won't run if the level of R-134a is too high or too low. It has to be exactly right. I paid a shop about $100 to do a level check / recharge when the car was 3.5 years old. It's been fine since, but I suspect it may need to be done again in the next year or two. Just consider it general maintenance that needs to be done, like tires or brakes.

Simple solution...take it to a different mechanic.

I don't know if it's true, but I have been told by a reputable source that all Honda's shipped out of Japan are slightly low on freon. This is to accommodate the multiple different elevations the car could be shipped to.

When our Fit was about a year old, my wife's dealership checked it out and found the refrigerant level to be slightly low. No leaks. Here we are 8 years later and it still blows ice cold after they added refrigerant.

I suspect that your mechanic isn't making sure it's at it's max freon capacity. He's probably checking it and it's within range vs being full.

You are icing up the evaporator.
So forget the following in your list :
Cabin air filter
Condenser fins
Expansion valve
Compressor

So what does that leave you?
Low refrigerant.
Evaporator sensor.
Compressor relay not turning off.

Low refrigerant should not cause a problem because the evaporator temperature sensor should turn off the compressor if it is running too cold. You could add a little refrigerant (a 5 minute job) to make the minimum temperature that the evaporator can operate at something above freezing. I usually shoot for 34 to 36 at the evaporator or 39 to 40 at the center A/C vent.

The Evaporator sensor should turn off the compressor at 40F +. It could be bad allowing the evaporator to run colder than freezing. I have not changed one a FIT but on some other vehicles you have to pull the whole dash apart to get to it.

There are some tricks that can be done to the external wiring by adding a resistor to fake out the computer when it sees the sensor. This is probably way above your mechanics skill level.

Compressor relays sticking seem common on Hondas. I do not know why. So if you want to shotgun this and replace the replay, have at it. It is simple to do.

If it were my vehicle, and not under warranty, I would add a little R-134 and watch the center vent temperature with a $10.00 meat thermometer from Walmart. Try to get it never to read under 40F in all driving conditions. If the evaporator can not evaporate below freezing then you do not need to worry about the sensor.

You are in a low humidity environment so it takes a while for the cold evaporator to accumulate enough moisture and freeze up using outside air. It will take even longer to freeze up using recirculated air.

If it does freeze up, keep driving and simply turn off the AC for a few minutes while leaving the fan on. The evaporator ice will melt while you are driving. You will actually feel the air getting colder as the ice melts and then get warm again after most of the ice has melted. At that point, or even sooner, turn on the AC again and continue on your way.

If your mechanic is using an AC machine, and not gauges, odds are he will not know how to add a little extra R-134. You can do it yourself with a can of R-134 from Walmart and a single gauge recharge hose, also from Walmart.

Or you can stop by here is NW Indiana anytime and I'll add a few ounces of refrigerant for free. I buy R-134 in 30 pound containers.

Sorry, there is no 'one size fits all' fix.
If the system has 100 different parts, there will be that many different possible things to fail, in twice as many different ways.

There are several things that are relatively common failures. Symptoms of each are vastly different if one knows what they are looking at/for, but to the appliance user the system simply doesn't work.

The casual observer/average driver only complains that "it quits working" and then whines about sweating and being uncomfortable, with little or no critical information about what the system was actually doing.

Much more information is needed before any sort of real internet guesswork can be done.



The guess about icing up the evaporator is a good one, BUT if this were the case the driver surely would have noticed a significant decrease in airflow from the dash vents as a small iceberg was clogging the ductwork, and the HVAC blower fan was still running on full blast.

If that wasn't noticed, then you'll probably have to drive it until it stops working, stop the car, open the hood, and observe whether or not the compressor clutch is engaged, and whether or not both radiator fans are running......Wait wait wait---FIRST you have to make sure you can tell if all of these are working or not so you know what you are looking at when the system stops cooling and you open the hood.

If your mechanic can't figure this out, he is broken and needs to be replaced with someone who actually knows about MVAC and can troubleshoot problems (a lost art IMO). The system will likely have to act up in order to be diagnosed, so someone may need to let it run for hours or take it on the highway to duplicate the problems, and he might need to take system low side and high side pressure readings while it acts up.

Slow airflow trough evaporator (due to restricted cabin filter or defective fan motor that spins slower than needed) will cause evaporator freezing and /or short cycling of the compressor with long pauses between cycles

Actually there is no difference between reduced air flow due to a partially clogged filter and turning the fan speed down. It should not freeze under either condition.

Found the right answer:
"The problem of car AC lines freezing up is caused by moisture that has been introduced into the system. ... Moisture in the system can freeze at that point, blocking refrigerant flow through the valve, and you'll notice you have warm air coming out of the vents."
The question is now how the moisture got introduced into the factory charged system?

We are not talking about refrigerant freezing. If there is moisture in the refrigerant system it would be captured by the dryer.

We are talking about moisture accumulating on the outside of evaporator. The moisture is condensed from the outside or recirculated the air passing through / over it. This condensation is normal and the condensed water normally runs off through a drain hose and on to the ground. If the evaporator surface is too cold then the moisture freezes and does not run off.

If the refrigerant system has not been opened and is still under some pressure, there is no way for moisture to get inside and mix with the refrigerant (r-134). When a system is opened up, we always replace the dryer and pull a vacuum to remove any air and moisture prior to recharging.

Agreed. The system is designed to cycle the compressor OFF when the evaporator core reaches about 37*F.

OP has not confirmed if the system cycles properly, or not.
OP has not confirmed if the compressor is, or is not, still engaged whenever the system quits cooling.

I also wonder if OP has a manifold gauge set?

You sure it's still got the original charge in itt? (FWIW it could have come from the factory like that, they are staffed with humans too)


A system discharged (or punctured as in crash damage) and left open to absorb moisture from the atmosphere coupled with insufficient deep vacuum level and time, saturated dessicant, poor work practices, and/or contaminated source refrigerant and/or equipment would be some likely causes IMO.

If one has an AC manifold gauge set connected to the system while the problem (moisture contamination causing internal freezing of the expansion valve) is actually acting up, one would be able to see a dramatic change in system operating pressures while it's happening.
Also, there would be no decrease in airflow through the dash vents if this happens, the only change noticed would be the temperature increase.

Thanks for all of these responses everyone. I am providing the thread to my mechanic and will let you know how it goes.

Bill

Make him do some diagnosis with gauges and a thermometer. Do not let him start throwing expensive parts at it.

Stick a thermometer int he vent and see what the temperature is coming out of the vent. It should never go below 40. Most vehicles run in the 42-44 range at the vent. It is slightly colder at the evaporator.

Run it until it fails and then check to see if the compressor is running and cycling. Park it (not running) and see if a lot water runs out of the bottom over the next hour at the ice melts off. Some water runoff is normal.

Update after dealer visit
 

I opted to take the Fit to my dealer on Friday. Been going there for nearly thirty years and they are straight up.

Same result as with my mechanic. They could not get the system to fail. Ran the a/c for 2 hours with the car parked. Air was ice cold. My buddy the service manager had speculated that the problem could be electrical, whereby the a/c relay could overheat in driving. We opted to replace the relay since it was relatively inexpensive ($40.00). Now I need to do a road trip to see if the problem persists. If it does, next area according to him and the a/c tech would be the compressor clutch. If we go there I'll be going after Honda to kick in some $$ since it is obvious by the responses on this forum that the Fit does have an inherent problem with the a/c on long trips.

FYI the system checked out fine in terms of refrigerant level, leaks (none), etc. And I had just swapped out the cabin filter so that was not the problem.

Hope to hit the road within the next month and I'll post the results.

Bill

You did not mention the air temperature at the vents which is the primary question here.

Parking the car and running it at an idle is a poor test for two reasons.

1. At the an idle the AC compressor is running at less than 1/2 capacity.

2. Accumulated heat at the evaporator and engine will be much higher than running down the road. The system will never get down to the freeze up level.

Throwing a relay at it was a good guess. Let's see if it did any good.

If you haven't done it and Honda did not monitor it, go buy a meat thermometer from Walmart in the housewares section for $10.00 and install it in the center vent to monitor the air temperature to see if this is really a freeze up problem.

Good Luck

Totally agree. I knew the parking test wasn't going to yield any results.

I'll do the meat thermometer test when I take my road trip and will let you know. Thanks for the quick and informative reply.

Bill

Plan your road trip so you can have the system acting up AND arrive at the dealers service department while it's still acting up. DO NOT shut the car off, leave it running so they can verify you really have a problem and see why

Because if you shut the car off, the problem and all the evidence disappears.

:yeahthat:

Road Test Results Are In
 

I just completed a 230 mile round trip from my home in Los Angeles to Barstow, CA Began the trip at 9:40 AM, arrived back home 1:09 PM with a 13 minute break at a Home Depot in Barstow.

As I previously mentioned, I had my mechanic and my Honda dealership both check the car out. They could find nothing wrong with the a/c. I had the dealer replace the a/c relay with the hope it would solve the problem.

It didn't.

The test was conducted using a Weber digital meat thermometer inserted into the Fit's center vent. I was unable to get anyone to go with me so I had to log the times and cycle on/off temperatures myself which is why the times vary a bit. Still, you'll get the idea once you take a look at them.

Summarizing the results: the a/c works fine to starts, then gets colder, then ramps up the temperature until it stops working completely between roughly 64 and 66 degrees. Thanks for any advice/thoughts that you folks can offer.

My apologies for the formatting.
Here goes:
Time Cycle On Cycle Off Fan Setting 09:40:00 AM 83 - 4
09:45:00 AM 46.5 52.3 4
09:53:00 AM 43.8 51.1 4
09:59:00 AM 40.3 45 4
10:01:00 AM 39.3 46 4
10:04:00 AM 38.7 46.2 4
10:06:00 AM 37.6 44.8 4
10:09:00 AM 36.8 45.1 4
10:11:00 AM 38.3 44 4
10:14:00 AM 35.9 45.2 3
10:15:00 AM 34.4 44 3
10:20:00 AM 35.7 43.4 3
10:25:00 AM 36.8 44.7 3
10:30:00 AM 37.2 43.7 4
10:40:00 AM 23.9 36.6 4 Weird low readings, thought thermometer was malfunctioning. Went to into teens, then single digits, then settled in 20’s. Lasted a minute or two. 10:45:00 AM 25.8 35.8 4
10:47:00 AM 42.5 49.1 4
10:50:00 AM 40.5 44.7 4
10:52:00 AM 44.9 50.2 4
10:55:00 AM 45.4 51.2 4
10:59:00 AM 47.6 53.5 4
11:01:00 AM 49.4 54.6 4
11:03:00 AM 50 55.5 4
11:04:00 AM 51.1 56.3 4
11:06:00 AM 52.8 57.2 4
11:13:00 AM - 64.6 4 Exit Ave. L Barstow, 115 miles. Park at Home Depot. Compressor spinning but not cycling. Fans working. Turn off engine, go into Home Depot. 11:26:00 AM


Car “peeing” water like race horse. 11:29:00 AM 62.5 - 4 Started car, beginning temperature 11:32:00 AM 41.5 45.2 4
11:34:00 AM 41.3 46.9 4
11:37:00 AM 40.3 46.9 4
11:41:00 AM 39.2 44.9 4
11:44:00 AM 38.7 45 4
11:50:00 AM 39.5 45.9 4
11:55:00 AM 40.3 46 4
11:57:00 AM 40.6 47 4
12:00:00 PM 41.4 47.4 3
12:05:00 PM 40.1 47.1 3
12:12:00 PM 38.3 44.3 3
12:17:00 PM 38.2 45.3 3
12:22:00 PM 41.7 47.4 4
12:24:00 PM 43.3 49.1 4
12:27:00 PM 44.7 50.5 4
12:29:00 PM 45.1 50.8 4
12:32:00 PM 46.2 52.1 4
12:35:00 PM 46.9 52.4 4
12:38:00 PM 48 53 4
12:42:00 PM 48.9 53.9 4
12:44:00 PM 49.4 54.4 4
12:46:00 PM 49.7 54.8 4
12:49:00 PM 50.1 56 4
12:52:00 PM 51.5 57.4 4
12:56:00 PM 53.6 59.3 4
12:59:00 PM 57.4 59.5 4
01:01:00 PM 57.7 60.2 4
01:06:00 PM 55.3 61.2 4
01:08:00 PM 56.7 61.5 4
01:09:00 PM 58.6 63.3 4
01:10:00 PM - 66.8 4 Arrive home. Park. Compressor spinning but not cycling. Fans working. Observed water under car again.

Center Vent Test Results 2012 Honda Fit A/C Road Trip
 

As was suggested by several forum members, I placed a meat thermometer in the center vent of my 2012 Honda Fit Sport and took a road trip to test the A/C temps. I drove 230 miles round trip from Los Angeles to Barstow and the A/C failed exactly like it did on my last three Las Vegas trips. In each case at approximately 90 minutes into the drive the A/C blows warm air. I ran internal air, max cooling.

Here are the results:

Time Cycle On Cycle Off Fan Setting
9:40 AM 83 - 4
9:45 AM 46.5 52.3 4
9:53 AM 43.8 51.1 4
9:59 AM 40.3 45 4
10:01 AM 39.3 46 4
10:04 AM 38.7 46.2 4
10:06 AM 37.6 44.8 4
10:09 AM 36.8 45.1 4
10:11 AM 38.3 44 4
10:14 AM 35.9 45.2 3
10:15 AM 34.4 44 3
10:20 AM 35.7 43.4 3
10:25 AM 36.8 44.7 3
10:30 AM 37.2 43.7 4
10:40 AM 23.9 36.6 4 **Weird low readings, thought thermometer was malfunctioning. Went into teens, then single digits, then settled in 20's. Lasted a minute or two.
10:45 AM 25.8 35.8 4
10:47 AM 42.5 49.1 4
10:50 AM 40.5 44.7 4
10:52 AM 44.9 50.2 4
10:55 AM 45.4 51.2 4
10:59 AM 47.6 53.5 4
11:01 AM 49.4 54.6 4
11:03 AM 50 55.5 4
11:04 AM 51.1 56.3 4
11:06 AM 52.8 57.2 4
11:13 AM - 64.6 4 **Exit freeway, park at Home Depot. Leave engine and A/C running. Pop hood. Compressor spinning but not cycling, both fans operating. Turn off car, go into Home Depot.
11:26 AM **Return to car, observe stream of water "peeing like a race horse from underneath car.
11:29 AM 62.5 - 4 **Started car and A/C.
11:32 AM 41.5 45.2 4
11:34 AM 41.3 46.9 4
11:37 AM 40.3 46.9 4
11:41 AM 39.2 44.9 4
11:44 AM 38.7 45 4
11:50 AM 39.5 45.9 4
11:55 AM 40.3 46 4
11:57 AM 40.6 47 4
12:00 PM 41.4 47.4 3
12:05 PM 40.1 47.1 3
12:12 PM 38.3 44.3 3
12:17 PM 38.2 45.3 3
12:22 PM 41.7 47.4 4
12:24 PM 43.3 49.1 4
12:27 PM 44.7 50.5 4
12:29 PM 45.1 50.8 4
12:32 PM 46.2 52.1 4
12:35 PM 46.9 52.4 4
12:38 PM 48 53 4
12:42 PM 48.9 53.9 4
12:44 PM 49.4 54.4 4
12:46 PM 49.7 54.8 4
12:49 PM 50.1 56 4
12:52 PM 51.5 57.4 4
12:56 PM 53.6 59.3 4
12:59 PM 57.4 59.5 4
1:01 PM 57.7 60.2 4
1:06 PM 55.3 61.2 4
1:08 PM 56.7 61.5 4
1:09 PM 58.6 63.3 4
1:10 PM - 66.8 4 **Arrive home. Compressor spinning but not cycling. Both fans working. Observed water under car again.

So basically I have a car that I can take on trips and drive for about an hour with cool/cold A/C. Then I have to pull over, take a break and then do another hour. It sucks. Thoughts on what is going on here? I feel like this should be a recall issue for Honda since based upon the responses on this forum and several Internet searches I've conducted this is a widespread problem with 2nd Generation Fits.

As usual, I really appreciate any help/thoughts/advice you guys can offer.

Bill

Those very low temperature readings, if accurate, are way too low. That would confirm (in my mind) the evaporator core is freezing into a huge ice cube.

The lake of water after the car had been left shut off would be supporting evidence of the huge ice cube. (ice cube melted after AC was shut off)




Doesn't airflow from the dash vents diminish or stop completely when this freeze up occurs??

Seems to me that after the core has had sufficient time and low temp to freeze solid, the slowly rising vent temp may be because there is little to no air flow through the core.



Next thing would be to figure out why the system quit cycling and kept the compressor running. You said you observed the radiator fans continue to run, that tells me the PCM is still seeing the valid AC request for whatever reason, and the PCM controls the fans and compressor. So not a relay issue at all.

Probably will be a game of swaptronics at this point, I'd guess either the temp sensor or the control panel.
Actually, after looking at the cycle temps again, it seems that 10*F or greater span from off to on is quite a bit wider than I'm used to seeing. I might guess at the HVAC control panel first.....but at the same time the thermocouple is probably the cheaper of the two to try (but a LOT more work).

Got a friend with an identical car you can swap the control panel with as a test?

Problem solved - Low Freon!
 

Thanks to the feedback provided by several forum members my Fit is now blowing cold a/c on long trips. The problem was low freon. I took my Fit to my dealer and shared the low freon diagnosis with the service manager. He agreed that could be causing the evaporator ice up problem. They did an a/c service and discovered two things: 1. They system was low on freon; 2. There were no leaks. After a recharge, I took the care on a 2 hour round trip in 90+ degree heat and the a/c blew cold the entire time. So the problem is fixed.

Frankly this makes me think that Honda, either by accident or on purpose to save money, charged the 2nd generation Fits with low amounts of freon. Since few people do more than commute in the cars the problem seldom shows up unless one of us owners takes a long trip. My car has done this since I bought it.

At any rate, thanks to all on this forum who stepped in with savvy advice and help. I truly appreciate it.

Bo;;

Sorry, meant "Bill."

Darn typos!

Great to hear! Go back to my first post and you'll see that's exactly what we found with ours when new. It just wasn't full from the factory. Unbelievable, but 9 years old now and the A/C still blows cold. Literally knocking on wood now. LOL

Good News.

I kind of of thought that was your problem after your first posting. I'm happy you found the issue. Yours is not the first Fit that has had this issue. The problem is getting a tech to do more than just stick a machine on it and say it passed. Most techs at dealerships have limited AC diagnostic ability and have no clue how to diagnose a problem when the machine does not do it for them.

At least you are happy now and that is what counts.

So I hate to revive an old thread but I’m in the same boat as the OP was. I have a 13’ sport with 45k that had the warm AC on long trips. I had the Freon charged as it was low, it last two weeks and now the compressor won’t turn on. Took it back to the shop who charged it last time and the Freon is low again. They added dye and can’t seem to find any visible leaks. I hate to think about ripping the dash out for the evaporator or expansion valve. Am I missing something obvious?

As noted, when the Freon is low you'll have issues on a longer trip (In June, I was running the PA Turnpike between Harrisburg and Phoenixville). Mine had visible ice on metal line under hood and the 'behind dash unit' must have had ice on it too from amount of water that drained out when I let the car sit at each end of the trip.

If you're low on Freon again, adding dye is the next step. Hopefully the leak is in / around the compressor, which does wear over time.

Harbor Freight sold a nice UV flashlight for $8.

If you can not find the leak using dye, the next step is to use a sniffer. If it leaks down in two weeks a sniffer ought to be able to detect it easily. You probably can find it without running the vehicle. Many times the leak is behind the compressor pulley and you can not see the dye but a sniffer will find it. If that does not work, start the car and tun on the fan on low and sniffer the vents. It fhe the leak is in the evaporator the vent fan ought to force some of the R-134 gas out mixed in with the air and you can sense it there.

I was in Walmart this morning and R-134 was $4.88 per can (except in Wisconsin for some reason). You might go through a couple of cans finding the leak.

Appreciate the reply. They couldn’t find the leak after looking for almost 30 minutes. I’m not sure if they have a sniffer. I had them recharge it again and they put dye in it. My biggest fear is that it’s in the evaporator or expansion valve. I really don’t want to tear the dash out of my 45k vehicle.

A sniffer is fairly cheap and any decent shop should have one around. Here is a cheap one on ebay.
https://www.ebay.com/itm/Refrigerant...sAAOSw6eldwQIB

When using dye, it sometimes helps to look in the dark and only have the UV light on. The dye will stick around even if the R-134 has leaked out.
Do not worry too much about evaporator leaks, they are not common. Usually I find leaks around connections (o-rings) and mostly compressor seals. On a Fit, many times a rock has hit the condenser because it is up front and fairly low to the ground. Look very closely at the front of the condenser. You can get a Black Light flashlight from Harbor freight for $9.00.