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Mazda6 Interior & Passenger Comfort Issues
- 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