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Mazda CX-9 Heat and Air Conditioning



  • So does anyone have a definate answer and or parts replaced to the mystical "rear air coming on full blast after turning off vehicle myth" I just picked up a used 2007 CX-9 and the day I brought it home (Friday) I turned it off and the rear air blasted on itself, I came back to leave on the car about 15 minutes later and it was off....

    So does anyone have a definate answer? Any Mazda techs out there that have encountered or fixed this issue?

    I am out of warranty so if it just a switch or a relay a part number and location is all I need to purchase it and install it myself. Thanks!
  • Check out the "new member thread" he is a Mazda tech. I asked him, see his reply below

    If you're referring to the blower motor (fan for air coming out of the dash vents--front blower, or fan for air coming out of the vents on back of center console--rear blower), TSB 07-008/09 addresses that issue. If you haven't driven 36,000 miles yet, take your vehicle into your nearest dealer and mention the TSB number listed above.

    However if you're referring to a radiator/condenser fan under the hood, that may run to cool the motor when you turn the car off.
  • Thanks! This is super helpful. My dealer tech seemed baffled since the problem wouldn't happen when the car was with them. Now I have something to go back with since I am still in warranty. Really appreciate your help.
  • cericceric Posts: 1,093
    Dealer has access to electronic versions of TSBs.

    Last time I printed out TSB when I visited my dealer, the service advisor returned it to me and said, "We can find it on our computer."
  • My CX9 is out of warranty so I asked my buddy that works at Riverside Mazda to hook me up with a copy of TSB 07-008/09. I read through it and was very simple and straight forward. I bought the relay that the TSB said to replace (part# G115-67-730) replaced it (under hood relay box closest to the driver's side fender) and up to right now no more occurences.
  • we are NOT car people. have a 2007 Mazda cx9. when you turn the key off and remove the key the air conditioning stays on and you can still make the windows go up and down. the A/C turns off after about 30 seconds to a minute. is this some new thing or is our electrical system messed up? thanks in advance for the help.
  • imamgimamg Posts: 136
    There is a window of time that allows you to still use the windows, this is normal... the ac/ staying on after the car is turned off is not normal...and there's a known issue with it. There's a relay that hangs open too long. Ask your dealer about it. It's not a difficult repair.
  • I have a 2008 CX9 and took my car in today as it was doing the same's the relay switch and they are charging me $149 to fix it...I wish I had researched it more before paying so much!!! If you are past the 36k warranty, it's not covered...
  • WOW! $149 to open hood, pop off relay box lid, remove both front and rear blower relays, install 2 X $20 relays, snap relay box lid back on, close hood and voila!!
  • cericceric Posts: 1,093
    There is a reason why knowing your vehicle costs you much less in maintenance.
    If the same had happened to me, I would read the TSB first, and try it fix it myself if my CX9 was out of warranty.

    Another thing people should consider is it to call MazdaUSA corporate. If you argue your case calmly, Mazda could pay for the parts, and you pay for the labor cost. It helps, but not entirely. This is especially true when your CX9 is barely beyond 36K miles.

    Anyway, early models (2008) have more problems (already better than 2007).
    Buying a 2010 model should be a much safer decision.

    I personally am not aware of any vehicle that is problem-free. My co-worker's Lexus RX330 already had two stall issues. That is a much bigger problem than the A/C staying on. You got stranded for THAT. And, yet, he seems to still love
    his "reliable" Lexus. Go figure. ;)
  • coachizcoachiz Posts: 9
    I've already had the phantom "blower comes on after turning off the vehicle" problem. The dealer replaced the front blower relay (#G11567730 MSRP $15.36) in warranty & now the rear blower relay intermittently does the same thing now that the vehicle is out of warranty - make sure you have the dealer replace both if the vehicle is in warranty - live & learn from my mistake.

    The new problem is in the AC but is totally separate of the relay problem. After many days of 90 degree weather & constantly running the AC, I began to hear a swishing sound under the dash. On left turns, the swishing sound would be accompanied by a fan & swish sound like a boat propeller entering the water. After a few days, the noises were accompanied by moisture on the passenger mat & all around the underside of the dash. After reading many posts, I determined I had a clogged AC evaporator tube. I found the tube outlet under the vehicle & blew out the obstruction with an air compressor hose. The water caught in the evaporator came gushing out. The good news is that I cleared the obstruction - the bad news is that during this entire process, my front blower has stopped working while the rear blower continues to work. The AC is working but you have to sit in the back to stay cool. I checked the relay to see if that may be the problem but it wasn't. I checked all fuses related to the front blower but they're all good.

    Has anyone had this problem - I'm guessing I may have fried my blower motor but I want confirmation & history before I rip my dash apart?

    Please help!!!
  • wwestwwest Posts: 10,706
    "..blew out the obstruction..."

    No, you blew the "obstruction" (mouse nest??) BACK into the A/C plenum area where it is blocking the blower from turning.
  • wwestwwest Posts: 10,706
    For many of us, maybe even the clear majority, DRY and COOLISH airflow continuously directed to the face and upper body can be discomforting, VERY discomforting. So I often override the automatic functionality and re-route cooling airflow to the footwell vents.

    The above is especially true when the human comfort equation tilts to the heating side, COLD surrounding outside landscape, and the system still INSISTS on routing cool and DRY airflow to the face and upper body.

    NipponDenso, Denso US, IDIOTS ALL...!!
  • wwestwwest Posts: 10,706
    edited July 2011
    "..let's discuss how effective floor vents are for the perceived cooling of the vehicle.."

    And now let's broaden the discussion....

    Yes, our "perception" of rapid cooldown of the vehicle is heavily influenced by the boundiful level of cool and dry airflow that is automatically routed to our face and upper body in cooling mode. BUT ONLY IN COOLING MODE.

    What about when the human comfort equation has tilted toward the need for HEATING, the surrounding landscape is COLD, and these systems still go into COOLING mode, coolish and DRY system airflow from the dash outlets.

    It is at those times, mostly, that the system needs to remain in, switch into, footwell airflow outlet mode.
  • wwestwwest Posts: 10,706
    "..I have a hard time believing it..."

    Believe it...!

    Most modern day climate control systems when in automatic mode and the cabin temperature is with a few degrees of system setpoint will ONLY route airflow via the dash outlets. (Doesn't mean you can't override it.)

    If you look at the internal design of the A/C plenum area, blower, evaporator and heater core placement, you can easily see that it was designed primarily for dash outflow, "cooling" mode.
  • wwestwwest Posts: 10,706
    When you first start your car the blower motor speed will be zero or surpressed until the engine water jacket was to ~130F, heating mode, or if the A/C evaporator isn't "cool", for cooling mode.
  • wwestwwest Posts: 10,706
    edited July 2011
    When you manually override a function in most new climate control systems ONLY that single function drops out of "auto" mode, everything else, unless also manually overriden, remains under automatic control.
  • wwestwwest Posts: 10,706
    My '95 LS400, ~800 miles "outgoing" got 25MPG hwy, 70+MPH, with the A/C on. Return trip was 28MPG with A/C compressor disabled most of the trip.

    OAT for the entire trip was not so hot as to be really discomforting even with teh windows (tinted) up.
  • wwestwwest Posts: 10,706
    Your front A/C system has a reheat/remix blend door wherein the outlet air temperature can be moderated, modulated, independent of blower speed. Mostly likely the rear system does not so blower speed is used to modulate the cooling level.
  • wwestwwest Posts: 10,706
    edited July 2011
    Perhaps Mazda is even wiser than we think, or at least modeso than I thought.

    There is an aftermarket device, EED by airsept(.com), that can be used to keep the blower motor running (intermittently running, interval timer) up to a hour after you switch off the ignition.

    Absent DRYING the evaporator immediately after use via some method such as the EED you may soon encounter a serious level of mould and mildew odor as a result of the "leavings" of the microbes thriving in the cool, damp, and dank A/C plenum area.

    Even worse yet you may encounter a thoroughly MISTED, FOGGED over windshield about 3-5 miles down the road some early coolish morning drive absent an evaporator drying system.

    Mazda may now be using such a system.
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