AC went out - Troubleshooting the cause
#21
07-25-2010, 03:42 PM
If you haven't changed the cabin filter, try getting a new one. It could be the problem, but still shouldn't have caused it to freeze.
If nothing else, run it on recirculate to avoid high humidity. This recycles dryer air from inside the car rather than drawing in hot humid air from outside. Be sure to put it back on the fresh air setting before leaving the car sit as this allows the evaporator coils to dry out and avoids mildew buildup (another possible problem).
I know it's not the filter, I put new ones in ever couple of months. I mess with recirculate on/off at least several times per trip, most often to keep others' exhaust smells out.
#22
07-25-2010, 03:52 PM
I know this sounds weird but when my ac stopped working it turned out to be a cabin filter that was completely plugged up. I had been driving on gravel roads all weekend and i guess at some point it became totally plugged and stopped blowing cold. Anyway, it's an easy thing to check.
#23
07-25-2010, 04:21 PM
Mine freezes up all of the time.... Turn the fan speed to the max, set the lever to open circulation mode and hit the on off button putting it in the off mode until the evaporator thaws and turn the A/C on.... Wa La it's fixed.
#24
07-25-2010, 04:38 PM
A car air conditioner should never freeze up. I had the same problem (07 Sport). The problem was the thermistor (part # 80562-SLA-003). About an hours warranty work at the stealer.
Last edited by spreadhead; 07-25-2010 at 04:42 PM.
#25
07-25-2010, 05:11 PM
Automotive A/C units and HVAC units in houses freezing up is pretty common with the heat and humidity in this area .... If the thermistor is causing it, the thing the do is turn the knob to a slightly warmer setting and or use the open vent mode setting.... I've been through your area a couple of times an think it would be the same there as well though if I am remembering correctly you are at a higher altitude where it may be a little less humid.
#26
07-25-2010, 05:20 PM
As I remember it - and I can never forget it - the heat/humidity that can occur in Texas is unlike anywhere else in the world. Eight weeks of Basic at Lackland and seeing an entire Air Base get 'red flagged' in August has left an indelible impression on my brain.
#27
07-25-2010, 05:43 PM
Automotive A/C units and HVAC units in houses freezing up is pretty common with the heat and humidity in this area .... If the thermistor is causing it, the thing the do is turn the knob to a slightly warmer setting and or use the open vent mode setting.... I've been through your area a couple of times an think it would be the same there as well though if I am remembering correctly you are at a higher altitude where it may be a little less humid.
. I live in Tennessee and travel throughout the southeast USA (hugh humidity area). Before thermistor repair-freeze up, after thermister repair-no freezeup. The thermistor shuts the compressor off before the evaporator reaches freezing temperature. But, hey if continally fine tuning your A/C is your thing be my guest.
Last edited by spreadhead; 07-25-2010 at 05:47 PM.
#28
08-08-2010, 11:23 PM
2009 Fit no A/C on trips over 2 hours
We own a 2009 Honda Fit Sport purchased in July 2009. We noticed the A/C stopped working within a week of purchase during a 4 hour trip on a hot/humid day during July of 2009. The air was cool, but not cool enough to cool the car and the air flow was decreased. The A/C did not return to normal during this trip. Once the car was parked for awhile... the A/C returned to normal. We live in NH so we do not get this weather very often. This summer (2010) has been much hotter and much more humid. So far this summer, during 3 trips over 2 hours long, the car has lost A/C each time 2 hours into the trip. The A/C works again if the car is parked for about 1 hour. (I have only taken 3 trips over 2 hours in this car so the problem is very consistent during hot/humid weather). I have requested help from our Honda dealership and they have stated that they need to be able to see the problem. Set up appointment for them to drive the car and the temps dropped to the low 70's that day without humidity. They want to drive my car for the 2 hours and see the problem themselves. They are refusing us a free loaner vehicle and will charge us for the time if the problem does not repeat when they make the drive. Not sure what to do about this.... considering trading the car although we have no other problems and would love to keep it. Any ideas???? Anyone else having this problem? Seems like you would like to take a break 2 hours into a trip... but if you are running late or stuck in a traffic jam... it gets really uncomfortable fast with 90 degree temps!!! Help!!! 
#29
08-08-2010, 11:47 PM
What is happening is normal down here in East Texas though the first time I had the problem you are describing with my Fit was on the Mexican border.... The evaporator is icing up and it can be thawed out by putting the circulation selector on the open setting that lets fresh air in rather than recirculating and raising the the temperature control setting with the fan on the highest speed..... Once the car is comfortably cool raise the temperature setting a little and be sure to use the open circulation mode.
#30
08-09-2010, 11:18 AM
Sorry Coyote, freezing evaporators are not a normal condition regardless of ambient temps, in your car or your home. The longest trip I've made in my 09 is Atlanta to Montgomery during disgusting hot/humid temps. No issues (other than the damn compressor cycles too often for my liking, the opposite of the problem described).
It's either a design flaw or something is broken. The thermistor that turns off the compressor when the evap is too cold is the most likely culprit.
@julbie: you have adequately described the conditions. Talk to the Honda service manager and if he still refuses to fix then talk to the regional manager. Most states have lemon laws but they don't kick in until three attempts to fix the same problem followed with a fourth final attempt. Check your local laws.
I know how frustrating this is. I once had an Izuzu that did the same thing. This was in Colorado with relatively dry and not terribly hot conditions. Dealer refused to fix and there was no way to recreate without driving it for hours. Letting it sit and run for hours in the dealer's lot will not recreate the conditions and may damage the car (overheating exhaust). I wound up leaving the country (not caused by the Izuzu, but I didn't take it with me either).
edit: they should have a quick test for a faulty thermistor using a temperature probe and a multi-tester. I'm sure Honda has a written troubleshooting procedure. This isn't 1965...
It's either a design flaw or something is broken. The thermistor that turns off the compressor when the evap is too cold is the most likely culprit.
@julbie: you have adequately described the conditions. Talk to the Honda service manager and if he still refuses to fix then talk to the regional manager. Most states have lemon laws but they don't kick in until three attempts to fix the same problem followed with a fourth final attempt. Check your local laws.
I know how frustrating this is. I once had an Izuzu that did the same thing. This was in Colorado with relatively dry and not terribly hot conditions. Dealer refused to fix and there was no way to recreate without driving it for hours. Letting it sit and run for hours in the dealer's lot will not recreate the conditions and may damage the car (overheating exhaust). I wound up leaving the country (not caused by the Izuzu, but I didn't take it with me either).
edit: they should have a quick test for a faulty thermistor using a temperature probe and a multi-tester. I'm sure Honda has a written troubleshooting procedure. This isn't 1965...
Last edited by Steve244; 08-09-2010 at 11:33 AM.
#31
08-09-2010, 11:34 AM
Steve My research has shown me the problem can occur in automotive AC and that adding a touch of 'heat' re: not max cool will help cure the issue.
You are correct in your analysis regarding how it should work, however, I'm thinking the Fit AC is a minimal design for economy reasons and the real world environment can trip it up.
You are correct in your analysis regarding how it should work, however, I'm thinking the Fit AC is a minimal design for economy reasons and the real world environment can trip it up.
#32
08-09-2010, 11:50 AM
Shouldn't need a workaround. Adding heat makes the A/C work harder and less efficiently (unless you need to add heat to be comfortable).
I've had A/C in all my cars starting with my first, a 65 Chevelle that I installed aftermarket A/C myself.
I've owned toyotas (3), Izuzus (2), Chevies (2), Pontiacs (1), VW's (3), Mercury (1), Nissan (1), Volvo (1), Honda (3)...
I've lived in the southeast (Miami, Charlotte, Atlanta), north (Seattle), west (San Francisco), central (Salt Lake City, Denver) and in the south of France. I even had an air conditioned Citroen (hard to find).
The only problem I ever had was with the Izuzu in CO.
If this problem is more common in Fits (seems we have 3 or 4 right here: not mine
) it sounds like a TSB is in order...
I've had A/C in all my cars starting with my first, a 65 Chevelle that I installed aftermarket A/C myself.
I've owned toyotas (3), Izuzus (2), Chevies (2), Pontiacs (1), VW's (3), Mercury (1), Nissan (1), Volvo (1), Honda (3)...
I've lived in the southeast (Miami, Charlotte, Atlanta), north (Seattle), west (San Francisco), central (Salt Lake City, Denver) and in the south of France. I even had an air conditioned Citroen (hard to find).
The only problem I ever had was with the Izuzu in CO.
If this problem is more common in Fits (seems we have 3 or 4 right here: not mine
) it sounds like a TSB is in order...
#33
08-09-2010, 12:04 PM
on older cars they used to ice up when the fan speed was low relative to the cooling setting, we were told to run high fan speeds on the coldest thermostat settings to prevent ice up but I haven't heard of any newer cars icing up.
#34
08-09-2010, 12:26 PM
The thermistor is a potentiometer or rheostat that uses resistance to control the temperature of your A/C... If you add resistance your going to get colder air less resistance and the air won't be as cold.. Just turning the knob clockwise will allow the compressor to cycle and prevent freeze up of the evaporator so why bother with having it replaced?.... When the humidity is low, my temperature control is in it's coldest setting, vent is in closed position and fan speed on 1 or 2, frost can be seen coming from the vents after just a few minutes of driving. With the temperature heat index right at 110 degrees or over as it has been lately there is no way that I could justify changing a thing.... If your radio was too loud when it is turned all the way up you would adjust the volume and possibly the tone and balance controls to where it suits you and doesn't hurt your ears or make your dash rattle, your A/C controls allow you to set it where it works best for the existing heat and humidity conditions that you encounter.... Where I live it isn't at all uncommon to have the evaporator freeze up when the temperature controller is in the coldest setting, the ventilation is in the closed setting and the fan speed is low... That applies to home HVAC and window units as well... The unit in my house takes many gallons of water out of the inside air everyday and if the temperature is set low enough it too freezes up..... By the way, the owners manual that came with my car addresses the problem of the evaporator freezing up and advises using the closed vent setting in extreme situations or when cooling down the interior when getting into the car when ambient temperatures are high.
Last edited by Texas Coyote; 08-09-2010 at 12:43 PM.
#35
08-09-2010, 01:03 PM
no it won't (temp knob increase resistance through thermistor).
In integrated car A/Cs (single temp knob to control heat and A/C) the temp knob allows hot coolant to flow through the heater core and mixes air from this with air from the A/C coil. The thermistor's action isn't changed.
In aftermarket A/Cs that are not integrated with the car's heater, they have separate controls: the temp knob for the A/C alters resistance (or tension on a bi-metal strip if you want to go back that far). This is not the case for the fit.
In homes, the A/C should run more or less constantly. It really doesn't matter if you have it set at 50F or 78F. They are sized this way to pull out the maximum moisture. These don't ice up either unless there's a problem. Home A/Cs are a lot less sophisticated than a car's; they usually don't have an expansion valve (just an orifice) and they don't have a temp sensor on the coil. Not a good analogy.
Your analogy with the radio is fun but irrelevant.
I'll have to check my manual. If it advises what to do when the evaporator freezes then this is definitely a design issue with Fits.
In integrated car A/Cs (single temp knob to control heat and A/C) the temp knob allows hot coolant to flow through the heater core and mixes air from this with air from the A/C coil. The thermistor's action isn't changed.
In aftermarket A/Cs that are not integrated with the car's heater, they have separate controls: the temp knob for the A/C alters resistance (or tension on a bi-metal strip if you want to go back that far). This is not the case for the fit.
In homes, the A/C should run more or less constantly. It really doesn't matter if you have it set at 50F or 78F. They are sized this way to pull out the maximum moisture. These don't ice up either unless there's a problem. Home A/Cs are a lot less sophisticated than a car's; they usually don't have an expansion valve (just an orifice) and they don't have a temp sensor on the coil. Not a good analogy.
Your analogy with the radio is fun but irrelevant.
I'll have to check my manual. If it advises what to do when the evaporator freezes then this is definitely a design issue with Fits.
Last edited by Steve244; 08-09-2010 at 01:06 PM.
#36
08-09-2010, 01:20 PM
nope, not there (page 111 to 113):
The term "freeze" only appears in relation to anti-freeze. I think you made that up.
Airflow Controls
Fan Control Dial
Turn this dial to increase or decrease
the fan speed and airflow.
Temperature Control Dial
Turning this dial clockwise increases
the temperature of the airflow.
Air Conditioning (A/C) Button
If equipped
This button turns the air
conditioning on and off. The
indicator in the button is on when the
A/C is on.
Fresh Air/Recirculation Lever
This lever controls the source of the
air going into the system. When you
slide the lever to the side, air is
brought in from outside the vehicle
(fresh air mode). When you select
the side, air from the vehicle's
interior is sent through the system
again (recirculation mode).
The outside air intakes for the
heating and cooling system are at the
base of the windshield. Keep this
area clear of leaves and other debris.
The system should be left in fresh air
mode under almost all conditions.
Keeping the system in recirculation
mode, particularly with the A/C off,
can cause the windows to fog up.
Switch to recirculation mode when
driving through dusty or smoky
conditions, then return to fresh air
mode.
Using the A/C
If equipped
Air conditioning places an extra load
on the engine. Check the high
temperature indicator (see page 63).
If the indicator begins to blink, turn
off the A/C until the indicator goes
off.
1. Turn on the A/C by pressing the
button. The indicator in the button
comes on when a fan speed is
selected.
2. Make sure the temperature is set
to maximum cool.
3. Select .
4. If the outside air is humid, select
recirculation mode. If the outside
air is dry, select [fresh air].
5. Set the fan to the desired speed.
If the interior is very warm, you can
cool it down more rapidly by partially
opening the windows, turning on the
A/C, and setting the fan to maximum
speed in .
Dehumidify the Interior
Air conditioning, as it cools, removes
moisture from the air. When used in
combination with the heater, it
makes the interior warm and dry and
can prevent the windows from
fogging up.
1. Turn the fan on.
2. If the A/C is off, turn it on (if
equipped).
3. Select and .
Adjust the temperature to your
preference.
This setting is suitable for all driving
conditions whenever the outside
temperature is above 32°F (0°C).
To Defog and Defrost
To remove fog from the inside of the
windows:
1. Set the fan to the desired speed or
high for faster defrosting.
2. Select by sliding the lever.
3. Select . The system
automatically turns on the A/C (if
equipped). The A/C indicator will
not come on if it was previously off.
4. Adjust the temperature so the
airflow feels warm.
5. Select / to help clear the
rear window.
6. To increase airflow to the
windshield, close the corner vents.
When you select or , the
system automatically turns on the
A/C. This helps to dehumidify the air
and to defog the windshield. In either
mode, you cannot turn off the A/C.
When you switch to another mode,
the A/C returns to its original
setting, either on or off, as indicated
by the A/C indicator.
Fan Control Dial
Turn this dial to increase or decrease
the fan speed and airflow.
Temperature Control Dial
Turning this dial clockwise increases
the temperature of the airflow.
Air Conditioning (A/C) Button
If equipped
This button turns the air
conditioning on and off. The
indicator in the button is on when the
A/C is on.
Fresh Air/Recirculation Lever
This lever controls the source of the
air going into the system. When you
slide the lever to the side, air is
brought in from outside the vehicle
(fresh air mode). When you select
the side, air from the vehicle's
interior is sent through the system
again (recirculation mode).
The outside air intakes for the
heating and cooling system are at the
base of the windshield. Keep this
area clear of leaves and other debris.
The system should be left in fresh air
mode under almost all conditions.
Keeping the system in recirculation
mode, particularly with the A/C off,
can cause the windows to fog up.
Switch to recirculation mode when
driving through dusty or smoky
conditions, then return to fresh air
mode.
Using the A/C
If equipped
Air conditioning places an extra load
on the engine. Check the high
temperature indicator (see page 63).
If the indicator begins to blink, turn
off the A/C until the indicator goes
off.
1. Turn on the A/C by pressing the
button. The indicator in the button
comes on when a fan speed is
selected.
2. Make sure the temperature is set
to maximum cool.
3. Select .
4. If the outside air is humid, select
recirculation mode. If the outside
air is dry, select [fresh air].
5. Set the fan to the desired speed.
If the interior is very warm, you can
cool it down more rapidly by partially
opening the windows, turning on the
A/C, and setting the fan to maximum
speed in .
Dehumidify the Interior
Air conditioning, as it cools, removes
moisture from the air. When used in
combination with the heater, it
makes the interior warm and dry and
can prevent the windows from
fogging up.
1. Turn the fan on.
2. If the A/C is off, turn it on (if
equipped).
3. Select and .
Adjust the temperature to your
preference.
This setting is suitable for all driving
conditions whenever the outside
temperature is above 32°F (0°C).
To Defog and Defrost
To remove fog from the inside of the
windows:
1. Set the fan to the desired speed or
high for faster defrosting.
2. Select by sliding the lever.
3. Select . The system
automatically turns on the A/C (if
equipped). The A/C indicator will
not come on if it was previously off.
4. Adjust the temperature so the
airflow feels warm.
5. Select / to help clear the
rear window.
6. To increase airflow to the
windshield, close the corner vents.
When you select or , the
system automatically turns on the
A/C. This helps to dehumidify the air
and to defog the windshield. In either
mode, you cannot turn off the A/C.
When you switch to another mode,
the A/C returns to its original
setting, either on or off, as indicated
by the A/C indicator.
#37
08-09-2010, 01:25 PM
Check out Polaski's thread "DIY; How to lower your A/C temperature". It will substantiate what I said about the temperature control switch/thermistor.
#38
08-09-2010, 01:44 PM
Regardless of what the Gen2 manual says in the Gen1 cars the frost buildup on the evaporator is addressed in the manual.... I wouldn't have even posted in a GE thread if this wasn't a common problem that I have experienced in numerous cars and trucks I have owned.... You can take your car in and have them do whatever or just use the controls for the A/C to prevent moisture from freezing on the evaporator and stopping the flow of cool air.... It is a cool 94 degrees outside so I am off to the barn to install the cable for my exhaust control valve that has to be welded in tomorrow morning.
#39
08-09-2010, 01:44 PM
Good thread.
He suggests adding a potentiometer (variable resistor) to the thermistor circuit to alter Honda's design resulting in less frequent cycling of the compressor and colder output (possibly resulting in freezing the evaporator if it's not adjusted carefully).
This is similar to other cars (Honda Civic) that have an economy mode for the A/C. Our Fits are designed to always run in economy mode.
He does not suggest the factory temperature control knob is a potentiometer. If you're unsure, ask him.
This supports the theory that those with freezing evaporators have a defective thermistor, not that they are running their air conditioners "too loud."
He suggests adding a potentiometer (variable resistor) to the thermistor circuit to alter Honda's design resulting in less frequent cycling of the compressor and colder output (possibly resulting in freezing the evaporator if it's not adjusted carefully).
This is similar to other cars (Honda Civic) that have an economy mode for the A/C. Our Fits are designed to always run in economy mode.
He does not suggest the factory temperature control knob is a potentiometer. If you're unsure, ask him.
This supports the theory that those with freezing evaporators have a defective thermistor, not that they are running their air conditioners "too loud."
#40
08-09-2010, 02:34 PM
When my music is too loud I change the volume. When my A/C evaporator ices up I change the temperature and (or) put it in the fresh air mode and (or) increase the fan speed and then it doesn't ice up..... You did notice that a potentiometer was installed in line with the resistors in Polaski's DIY thread? As long as I have cool air when I want it and adjusting the the controls allows me to set the temperature to where the evaporator doesn't ice up I don't see where there is a problem... Even in 100+ temperatures my wife wears a light jacket when riding in the Fit with the A/C on... I think that lowering the under hood temperatures with hood louvers has made a difference in lowering the A/C temperatures or the interior temperatures because it does seem that the car is cooler than it was prior to installing them.