I did not mod a Honda Fit. I did the mod on a Chevy Colorado. So the pictures and location of everything would not apply to your Fit.

If it were me doing it to a Fit, I would go get 3 resistors. 150K, 180k, and 220K. Then find that thermistor connector shown in the Fit mod writeup. I would slip the 180K resistor in the back of the connector so it is jumpered across the two connector pins (meaning wired in parallel with thermistor). Then go try it and see where the lower limit is using your digital meat thermometer. If you want to change it lower or higher simply replace the 180 K one with the 150k or the 220K resistor.

Those are standard size resistors and 1/8 or 1/4 watt ones will work just fine. Radio Shack should have them for less than $.50 each.

I would shoot for a vent temperature of 39 or 40 degrees. If you are more adventuresome you could go a little lower, but keep in mind that the vent temperature is a few degrees warmer than the evaporator itself. You will not hurt anything by going too cold. It will just freeze up the evaporator. The ice will melt when you turn off the AC.

 

^You didn't read my post did you?

Just get a 200k ohm potentiometer(that's a variable resistor in case you didn't know) and you can dial it in perfectly (using the meat thermometer) rather than guessing with random resistor values.

What if he needs less than 150k of resistance?

This is not a one size fits all problem. Everyone will need slightly different resistances because there is apparently a lot of variation in the thermistors being produced for the fit. We know this because of all the varied reports even in just this thread.

For example, I ended up with two pots in series each at 100k for maximum potential resistance(so basically a 200k pot like I suggested). But ended up dialing it down to about 80k ohms because simply dialing it down to 150 or even 100k ohms was not enough. I'm not saying anyone else will need to go that low, but it's much easier to do this mod with a potentiometer and fine tune the AC temperature.

 

Gotta say, my ac is super cold. Like frigid. I turn it off when it's too cold.


And I'm in Texas during summer. Humid and like 100 degrees.

 

Probabaly it won't but my Fit was measuring outside temp as 99% and the interior is leather, with Econ ON, car cooled down and became mildly cold within minutes. Your A/C is just not operating correctly. Make the dealer fix it, tell them it's so crappy you are sweating all the time. It's not acceptable!

And people pitching in mentioning that the A/C is weak on their GE, that's great, but it's obviously a different vehicle. My GK is COLD within minutes, even with the leather, and Econ on. Even without tint it should eventually get cold.

 

Agree with this. I have leather, no tint and even in 90+ degree days, the A/C cools very quickly in my Fit. Sounds like those with issues have a legit complaint and need to get to a dealer for a solution.

 

You are proving my point, I sincerely believe this is because of varying yields in thermistor production. And you just happened to be lucky and get a car with a "good" thermistor. Some of us (such as myself) weren't so lucky and had to use a resistor to compensate for our "bad" thermistors. The problem with my car had nothing to do with the AC system being old or over/undercharged. From the thread I posted, you can see that other people also fixed this issue by correcting the reading that the thermistor was giving to the computer. And that their AC systems were otherwise running fine.

Yes it's a different vehicle but it's the same company and still a fit. The underlying system and the way it works is exactly the same. Honda may have switched to a thermistor with different resistance values (although they were the same between the GD and GE), but adding a variable resistor will stil have the same effect.


It's definitely legit. They should check out their AC charge and get a diagnostic from the dealership for free. But, if it comes back saying that everything is okay and within spec yet it's still not cold enough, the mod I posted will do the trick.

 

I did read your posting. I chose not to use a pot because potentiometers that are not used (exercised) tend to become noisy and intermittent over time. I would rather go with a more permanent fix. Actually if I were to use a pot I would try it until I found the correct value and then replace it with a fixed resistor.

I have modified a few other thermistors in other vehicles and a few cent resistor is all that was needed.


Do as you please. A pot will work. At least for a short term (a year or two) fix. After that you may to spray it with some contact / pot cleaner and exercise it a bit.

 

Or just pay a dollar and put a new one in.

 

40 minutes in garage then 15 minute drive

Upper vents selected, recirculation, outer vents closed

 

40 minutes in the garage

Recirculation, upper vents old, outer vents closed

 

Now the thermometer i used is for my works server/router/data center so I figured it would be accurate for what I needed

 

The type of thermometer that works best is one with about a 6" stainless rod probe sticking out the back These are routinely used in heating and AC work and also for cooking. The one you show may indeed be one. I just can not tell from the picture.

I also see in the picture a temperature reading on the dash of 83 and 84. Is that inside or outside temperature. Normally we think of a 30 degree drop in temperature of the air coming in vs. the air in the center vent as acceptable. 40 degrees is obtainable in a properly operating system. With the engine at idle and the compressor running slowly, these cooling numbers may not be obtainable. I have done some work with alternative refrigerants and as a standard we usually use 1500 rpm for our measurements.

The thermistor mod we have referenced only changes the low temperature cutoff point. If you never reach that point due to a weak system then this mod will do nothing for you. From your picture we know that the cutoff point is at least 48 F and could be lower. I was out today with the AC on and my meat thermometer in the vent. Mine, which has the mod, usually cuts off at 39F. It usually goes to 39 F and shuts off. Then the temp slowly raises to about 45. Then the compressor starts again slowly sending it back to 39 F. One time it did go to 38.5 F.



I like this thermometer the best. It is digital, cheap, and usually available locally in the housewares section.

AcuRite Digital Meat Thermometer, 00641W: Kitchen & Dining : Walmart.com

Here are some others of this type:



Automotive Dial Thermometers | MSCDirect.com

 

Gauge temps are always for the outside.

 

Thanks. I do not have that indicator on my Fit. I assumed it was outside air temperature but wanted to make sure.

 

Not once did I see anyone suggest inspecting the AC condenser. It can have its fins bent up and blocking airflow, causing a pretty massive effect on AC performance.


I attempt to fight this with the purchase of a fin straightener from harborfreight. its basically a big plastic comb with a handle, and you simply drag it across the condenser/radiator equipment and slowly straighten them out.

Must be careful though!

 

Good point but less likely to be an issue with a brand new car.

While you're on the subject, don't forget to mention the AC condenser mesh protection DIY. It's saved me and others a lot of headaches/money!

 

Tmasazo,

Do you feel like that the AC is enough for you at that level? Or do you feel like something is wrong with it? Also have you taken it to the dealer? I'm curious.

 

No, the A\C does not feel like it is working. I have not taken it to the dealer yet. My friend who still works in service is going to trade me cars and take it in for me to get it checked.

I thought it note worthy that on cold mornings high 50's pulling air from outside AC off the air coming out of the vents is WARM not Cool. Now I believe the Air Duct is under the window like most cars but could be wrong.

Yesterday, I took the car from the garage where it had sat for 3 hours with windows down. Drove 30 minutes with AC full blast with recirculation on. outside temp was 88 degrees inside was 84..... does that seem right?

 

Yeah, advice is greatly appreciated but you should not even have to do a thermometer test. If it doesn't cool, it doesn't cool and it's brand new so the dealer needs to fix it.

 

If it didn't get cool at all, you have a problem. But, if it was cool and not cold, the computer regulates the a/c more fervently in the Econ mode of operation. Turning Econ off helps run the a/c colder. The mileage drop is slight.