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Mazda6 Interior & Passenger Comfort Issues

sgraesgrae Member Posts: 2
I had this problem twice; once in the summer of 2007, and again in the summer of 2008. The reason I am writing this note is to hopefully help anyone having a similar problem. Yes, it can be fixed. The trouble is convincing the dealer this is really a problem.


- A/C is not cold enough in summer.
- Heat is not hot enough in winter.
- Small changes to temperature dial cause big change in vent temperature.


- Claimed there was a refrigerant leak. Recharged A/C for no charge (under warranty.)
- Claimed 60 degrees is normal and A/C temperature depends on outside temperature. (One dealer said the A/C can only cool the outside temperature by 30 degrees. Another dealer told me the limit was 20 degrees.)


In the summer of 2007, I took my car to two different Mazda dealerships because the A/C wasn't cold enough. The first place was useless. They simply recharged the system and then claimed 60 degrees is normal for A/C. I called a friend's mechanic and he said A/C temp should be in the low 40's (with cooling on max and recirc on.) I then called a different Mazda dealership and they also said low 40's is normal, so I took my car to them. After a full day of searching, they got my vent temp down to 43! The mechanic said he finally found a loose wire on the "hot/cold rheostat." It worked great after that until the next summer.

In the summer of 2008, the same problem happened again. (A/C temp no cooler than 55 - 60 degrees.) The car went back to the "competent" dealership, but this time things didn't go so well. The same guy worked on the car and checked the original loose wire. That didn't work this time. So he did a leak check with a blacklight and said there was a very small leak caused by a bad O-ring. That was replaced and the A/C was recharged again. They said, "All fixed." Sadly, the vent temp was still 60 degrees. When I told them it was still too warm, they gave me the "it depends on outside temperature" story the first dealer told me back in 2007. Sheesh.

All of this was covered under warranty which was nice, but my A/C didn't blow cool air. On top of that, small changes to the temperature dial resulted in big changes to the vent temp. (For example, I changed the dial from 70 to 72 and the vent temp went from 60 to 90. Outside temp was around 70 at the time.)


Outside temperature is not the problem. That's a fact. This has been proven to me twice now; once by the second dealer fixing the problem, and once by myself. When the system was broken, 60 degree air came from the vent with recirc on and cooling set to max (60 degrees on my climate dial.) The outside temperature that day was low 80s. After the system was fixed a few days later, my vent temp was 42 degrees and the outside temp was 95. No lie! That's 53 degrees of cooling power. (95 - 42 = 53.)

Another myth is that it is normal for the computer to increase vent temp by 20-30 degrees when you change your knob one or two degrees. When the system is working properly, I have never seen it react more than 5-10 degrees for each degree I change the dial. (This is assuming the car has been running for a while.)


I worked on cars back in the early 80's, but I don't know much about computer controlled cars. At any rate, the dealerships ticked me off bad enough to get me under the dash to see what was going on. The good news is that I fixed the problem without doing anything in the engine compartment. The bad news is I am not exactly sure what fixed it.

All the fiddling I did was behind the glovebox. To remove it, open the door normally and press on the sides to allow it to open beyond the stop point. There's also a safety string hooked on the right side that needs to be removed. (Just slip it off.) After that, the bottom hinge simply snaps off. (Pull the door toward you.)

Inside the glovebox area, you will see the access door for the cabin air filter. Above that is a servo motor that controls the recirc flap. To the left of the filter are two more servo motors; one on top of the other. The upper-left motor controls whether air blows out of the top vents or the floor vents. The lower-left motor controls the hot/cold mix. This was the motor I was very suspicious of, especially since the mechanic who fixed this problem the first time said it was a loose wire on the hot/cold rheostat.

I removed the lower-left servo motor and then moved the flap by hand. To do this, I unplug several connectors that prevent me from getting a torx wrench on the servo motor. (I reconnected them after taking the motor out.) Moving those wires and connectors might be important, because as it turns out, the servo motor looked perfectly fine, and moving the flap by hand made no difference in the problem. (i.e. The air got hotter and colder as I moved the flap, but never colder than 60 degrees.)

While the servo motor was removed, I noticed a thin black wire pair (similar to speaker wire) running to the middle-back of the dash area. I reached back in with my hand and wiggled it a little. It seems to go into the evaporator part of the A/C system, but that piece is fairly buried so I couldn't determine what the wire was for.

Since the cold air was still only 60 degrees at this point when I was holding the hot/cold flap by hand, I reinstalled that servo motor and check the temp again. (Still 60 degrees. *sigh* So much for my original theory.)

Next, I removed the cabin air filter and place my hand into the opening to feel the temperature of the air flow. WARNING - CAUTION - DANGER! The airflow pulls your hand downward into the rotating fan, so please be careful while doing this.

I notice the air flowing through the filter box felt very warm. I turned recirc on and off a few times and saw the flap move, but the air temp didn't feel any different. I hit the auto mode again and then manually turned down the fan speed. (I repeat - "fan speed," not the temp knob.) Up to that point I was letting the computer control fan speed. My hand started feeling cooler! I checked my vent temperature and it was dropping below 60. Finally! After a while, I turned the fan speed up and the vent temp continued to drop. Even after I turned the auto-climate control back on, everything still worked.

One other possibility was that my engine was idling for around 45 minutes during my investigation. It is possible that something started working just because of that.


I'm not sure what finally fixed the problem, but that's everything I did as best I can remember. I really think I bumped a wire or connector that was loose. Or possibly there could be something wrong with the recirc flap. That servo motor always moved during my tests, but perhaps the flap wasn't seating itself correctly and allowing hot air in from the outside when it wasn't suppose too.

Best of luck to you in solvi


  • rswaffordrswafford Member Posts: 1
    THANK YOU!!!!!!!!!!!

    I know this is an old post, but it just helped me solve my AC problems. I have a 2005 Mazda6, and up till this year the AC has been nice and chilly, just how I like it. The first part of this year even (I live in Wisconsin...not much need for AC early in the year) it was great - then we took a road trip to Illinois on a 95 degree day an I realized the air just wasn't keeping up like it used to.

    I had a shop try a full AC flush and recharge to no avail, and was about to call the dealership when I found your post. All I did was go back under the dash and jiggle/reseat all the wiring harnesses behind my glove box - and as soon as I did that the AC magically started blowing closer to 40 degrees (down from 60)!

    So...from the bottom of my heart, THANK YOU!
  • wwestwwest Member Posts: 10,706
    You now have a DEFECTIVE climate control system.

    Modern day climate control system design is as much about PREVENTING occupant discomfort as they are about promoting comfort. Almost ALL modern day climate control systems MODERATE the heating and/or cooling mode such that the cabin occupants are not discomforted by EXTREMES.

    Set the temperature setpoint to 70F on a HOT sunshiny day and you will get fairly COOL system outflow initially, until the cabin air, atmosphere, is lowered to, say, 75F, and then the outflow will be moderated to maybe as high as 60F. Once the cabin atmosphere subsequently reaches within a degree or 2 of the 70F setpoint it might be moderated to 66-68F, just (barely) enough to hold the cabin air temperature at a relatively constant 70F.

    In my '01 F/awd RX300 if I wish to WARM up the cabin QUICKLY starting out on a cold morning I MUST set the temperature setpoint to the highest temperature (85F). Otherwise the climate control system will moderate the heat level of the system cabin outflow such that occupants are not unduly discomforted.

    The same is true of simple heating and/or cooling, once the cabin temporature has been raised to nearby your temperature setpoint, or lowered to nearby for cooling, the system will "moderate" the system outflow temperature such that the occupants are not discomforted.

    Also, once the temperature is within plus or minus a few degrees of setpoint in "heating mode', COLD outside (footwell predominant outlet airflow), it will still switch into cooling mode, cool, coolish, and DRY airflow to your face and upper body.

    It will still do this, switch into COOLING mode, on the darkest and coldest winter night provided the cabin air temperature is within your setpoint "bandwidth".

    My advice, and the practice I follow, is to use MAX cooling + recirculate or MAX heating, in accordance with my body needs, and then manually manipulate the blower speed for/as my "comfort" control. If the cabin still becomes too cool for my comfort I then turn off the A/C functionality, disable the A/C compressor clutch.

    Quite a nuisance to turn the A/C on and off as you travel throughout the day, but more comforting than what those idiot NipponDenso, Denso US, engineers think of as "comfort".

    Oh, my A/C compressor remains disabled throughout the coolish months.
  • mz6greyghostmz6greyghost Member Posts: 1,230
    edited July 2011
    You now have a DEFECTIVE climate control system.

    What's so "defective" about it? He jiggled a wire and it started working again, end of story, and it had NOTHING to do with your post about your "defective" climate control.

    And for the record, modern climate control systems work to the SPECIFIC TEMPERATURE that you set it at, then keep it there. That's what it's supposed to do. If the ambient temperature is dropping from the A/C, and suddenly the air gets slightly warmer, it means the system has reached the temperature that YOU set it at, and it's now maintaining it. It's not "defective", and there's nothing wrong with it.

    It sounds like you wasted your $$$ on an "auto" temperature-based climate control system on your Lexus, and now wish for a vehicle with the standard rotary knobs for the temperature and fan speed. They still make them.

    AFAIC, this is my second "auto" climate control system on my '10 Mazda6 (my previous '04 had it as well), and it's works beautifully.

    On cold mornings, it automatically kicks on the defroster and keeps the fan speed on it's lowest setting until the air gets warmer (usually in under 5 minutes), then gradually increases fan speed, then direction, until the windows are clear and it's at the set temperature. I almost never touch it in the winter months because it does exactly what I'd do.

    Summer? No problem there as well. In a hot car, the system switches to recirc air and kicks up the fan speed until the car cools off, then slows the fan and maintains the set temperature. Again, as designed.

    There's nothing "defective" about how an "auto" climate control system works, it's just not for some people used to the rotary dials or levers.
  • wwestwwest Member Posts: 10,706
    "..in a hot car, the system switches to recirc air.."

    Yet another design FLAW...!

    It should be pretty obvious to even a beginning HVAC design engineer that switching immediately to recirc is a mistake. The proper procedure would be to leave the system in "fresh" airflow long enough to PURGE the cabin of the atmosphere that is HOTTER than the outside, THEN switch to recirc.

    I'll bet even your owners manual points out this mistake. It will direct you to lower the rear windows slightly for a few miles in order to purge the HOT cabin atmosphere.

    Not many of us humans feel very comfortable with dry and cool, coolish, airflow directed to our face and upper body when the human comfort equation indicates the need for HEATING.

    Toyota and Lexus have recognized the design flaw and there is now a C-best option that prevents the system from going into cooling mode when the human comfort equation indicates otherwise.
  • mz6greyghostmz6greyghost Member Posts: 1,230
    It should be pretty obvious to even a beginning HVAC design engineer that switching immediately to recirc is a mistake. The proper procedure would be to leave the system in "fresh" airflow long enough to PURGE the cabin of the atmosphere that is HOTTER than the outside, THEN switch to recirc.

    That's right, lets allow the super-humid outside air to circulate into the cabin for a few moments while the occupant wants the cooler, DRYER air immediately. That makes sense... :confuse:

    The reason why it switches to recirc in the first place is to limit the amount of moisture in the air, as well as being more efficient by reusing the cooler air. Despite the fact that it may be warmer inside a vehicle when first starting out, the air is also not nearly as humid, and it's also something that HVAC engineers DO know.

    I'll bet even your owners manual points out this mistake. It will direct you to lower the rear windows slightly for a few miles in order to purge the HOT cabin atmosphere.

    Umm, nope, it doesn't. In fact, if I needed more than 30 seconds to feel at least some cool air coming from the vents, then I'd say the A/C wasn't working at all.

    So it makes more sense to keep the windows down for a few miles, then kick on the A/C? Umm, no thanks. Since most car trips are no more than a few miles, why bother?

    Not many of us humans feel very comfortable with dry and cool, coolish, airflow directed to our face and upper body when the human comfort equation indicates the need for HEATING.

    Actually, the typical "human comfort equation", or whatever name you give it, likes to be at a certain temperature, whether or not it's the winter or summer. That's why you have a thermostat in a home, office, and now in cars, to maintain that temperature, that's all it does. You make it sound like that it goes into full A/C mode when the car reaches the set temperature in the cooler months, and kicks on the heat in the warmer months. That simply isn't the case.

    Toyota and Lexus have recognized the design flaw and there is now a C-best option that prevents the system from going into cooling mode when the human comfort equation indicates otherwise.

    Then it sounds like Toyota has addressed a flaw in their climate control system that isn't found in any other maker today.
  • wwestwwest Member Posts: 10,706
    "...Another myth.."

    Most newer automotive HVAC systems, once the cabin ATMOSPHERE, AIR, has reached a point very close to your temperature setpoint, will "moderate" the system outflow temperature to within only a few degrees.

    Change the setpoint even 2-3 degrees and the system will react by raising/lowering the outflow temperature in order to most quickly reach your new setpoint, and then moderate begins....

    The radicalness of the outflow temperature swing upon a setpoint change is dependent on several not so obvious factors.

    1. The OAT, the outside air temperature.
    2. Sun's BRIGHTNESS, solar radiation level.
  • wwestwwest Member Posts: 10,706
    "..Im not sure what finally fixed the problem.."

    My best guess is you somehow locked the "blend" door/vane servomotor in the MAX cooling position, no airflow diverted to flow through the heater core so as to moderate the system outflow.
  • oldburbnewcx9oldburbnewcx9 Member Posts: 53
    Everything you said prior to explaining how radical the temperature swings and the obvious factors is exactly how a modern automotive HVAC system should operate.

    Wow.. I didn't even know that my car sensed the brightness of the sun.
  • sgraesgrae Member Posts: 2
    Awesome! Great to hear it helped.

    My A/C has been working great ever since I jiggled the wires, and I'm never going back under my dash as long as things are working. One wrong touch of a wire could screw up the A/C again.
  • natb1natb1 Member Posts: 10
    09 Mazda6 S Grand Touring 3.7L

    Just got the car 1 week ago, & already I need to find what is causing the following. I only have 2 months of factory b-b warranty, and I want to make sure the issue is addressed properly....especially if expensive factory parts are involved! Im thinking this is happening to others:


    * after 4 hours of drive time, with AC at maximum blower velocity and minimum temperature and NOT on “Auto”.

    * AC Blower velocity significant reduced.....especially in drivers side.
    * AC temperature not even “cool”
    * pulled over opened hood while engine running and AC still on.
    * The refrigerant line, leading into firewall, was frosted over.
    * turned AC off and waited 5 minutes.
    * investigated evaporator area under dash
    * Water was pouring out of Evap Box, and down onto the floor boards. ( no drain hose? )
    * Water was running out onto unidentified electronic control module and wire harness!
    * No Protective Loom or Jacket on wire harness either...... 8 \
    * Water came into contact with Heater Core OR “High Side (hot side) AC line”, then dripped on passengers feet, burning them.
    * water droplets were spitting out of passenger-center vent.
    * Next day AC "seems to work"

    Have only seen mentions of "cooling fan problems" on this car. Could this be the issue? I was driving Highway speeds the whole time....so never say engine temp go up.
    Can this cause the refrigerant line to frost over?

    Someone please point me to another post if it rings a bell.

    Im trying to avoid being placated with jive nonsense, or worse, for <60 days, when I will fully own the "real" problem with this car.

    Thank you in advance!
  • oldburbnewcx9oldburbnewcx9 Member Posts: 53
    Your system is low on refrigerant. Could be due to many reasons. You need to recharge the system and check for leaks. Read your warrenty to see what is covered, don't just quote b-b warrenty.
  • natb1natb1 Member Posts: 10
    Thanks, but I think I found the issue.

    I found the cabin filter last night (first car Ive had with one) and it was caked with yard debris. The "grating/screen" for recirculation is large....like a chain link fence. I even found a leaf the size of a 50 cent piece. Im 95% this is the problem, because it would certainly explain the frosting and excessive water after thawing. I would think the drain line could be more effectivie though....water running out of the box and onto the floor? Perhaps it was condensing on the outside of the plastic housing? Hmmm..

    I just need to take it for a long drive on a hot day.

    I will report any developments for the benefit of others.
  • nsbio1nsbio1 Member Posts: 75
    edited June 2012
    I do not know whether this is directly relevant to Mazda6 or not, but for Mazda3 there was a TSB for AC freezing over and starting to blow warm air after driving for extended periods of time at highway speeds with AC on and fan on low. I do not know what the resolution of that was, and my car has done this once, but if anything, the best remedy for future situations like that would be to crank up the fan a bit.
  • natb1natb1 Member Posts: 10
    hmm....thats interesting.

    I will need to investigate that.


    Anyone have a Mazda3 TSB list?
  • Kirstie_HKirstie_H Administrator Posts: 11,148
    edited June 2012
    I *think* I might have found one :)


    Once you enter details about your vehicle, you get a page with links to Recalls and Technical Service Bulletins.

    Need help navigating? kirstie_h@edmunds.com - or send a private message by clicking on my name.
    Share your vehicle reviews

  • john645john645 Member Posts: 1
    I have a 2010 Mazda 6 with a similar problem. After a few hours the aircon stops blowing cold air. You can hear the fan working, but less air comes out and its not all that cold. If you stop the vehicle for 10 minutes and restart - there is no change. But if you leave it for an hour or two, it works just fine again. What I believe is happening is that something in the air con is freezing up occasionally. Mazda seem unable to fix it. They tried (at least that's what they said) - but I think its a design flaw. Its an intermittent issue and luckily does not happen all that often. Good luck
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