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Mazda CX-9 Heat and Air Conditioning



  • wwestwwest Posts: 10,706
    The A/C blower may be running after the ignition is switched off in order to DRY the evaporator(s). Mazda may have a method of detecting just how much moisture is left on the 8,000, 10,000 square inches of evaporator, evaporators, cooling vane surface area and will operate the blower accordingly.

    See the EED write up at
  • coachizcoachiz Posts: 9
    edited July 2011
    I grabbed my Guinness Book of World Records & looked up the "Worlds' Smallest Mouse". Even Whiskers from Ocala, FL wouldn't fit in the drain tube or the plenum so I think I'll discount your mouse nest theory. The blower was dead before I moved the obstruction. Any more creative or helpful ideas??
  • wwestwwest Posts: 10,706
    edited July 2011
    Well, first, regarding mouse size. Some years ago, even after I had sealed every possible entry point, we kept getting mice inside the plenum area of our '94 Aerostar. It turned out that they were getting into the front cowl area and thus into the A/C plenum by squeezing through the tiny opening around the wiper posts.


    If the position of the squirrel cage blower motor/assembly is like many others today, motor below the squirrel blower itself and shaft vertically oriented, it's highly likely that water got into the motor commutator and brushes area.

    That wouldn't blow a fuse as the motor simply wouldn't draw any current.
  • davichodavicho Posts: 190
    I guarantee you this is not the case...Mazda has a TSB out for this concern and it states to replace the relays because the original relays do not have the proper load capacity to keep them off after ignition is turned off. It is simply an improper relay function and not a pre-set function of the HEVAC system.
  • wwestwwest Posts: 10,706
    Granted, what you're saying is possible, relay contacts not releasing, but i have my doubts.
  • wwestwwest Posts: 10,706
    "....I turned it off and the rear air blasted on itself..'

    "...15 minutes later and it was off..."

    That would mean the "relay" contacts closed just as/after the ignition was switched off. That IS NOT a function of a relay, ANY relay, that is known to man. Much more likely a logic flaw in the Body Electronics ECU firmware.

    Plus which, VERY few, if any, automotive HVAC blower motors are energized via a simple relay, most are transistor driven using a PWM technique to control speed.
  • davichodavicho Posts: 190
    Look it up TSB 07-008/09

    I did the relay swap per TSB and have never had it occur once again since.
  • wwestwwest Posts: 10,706
    Not a simple "passive" relay..?

    Having a relay fault wherein it closes the contacts asynchronously is unheard of.

    Having the contacts already closed and remaining closed after power is removed is certainly not unheard of and generally only happens after many hours of use, contacts "pitted".
  • Yeah this same thing just happened to my 2008 Cx-9 also, the blower motor just died Yesterday, I'm taking it to Mazda tomorrow, this is gonna suck.
  • tsd151tsd151 Posts: 1
    I would definitely look into other manufacturers. We bought a 2011 CX9 grand touring, loaded. Have had it for 3 months and live in Yuma, AZ where temps are routinely 110+. Pull up to a stop light and sit for more than 30 seconds and 95+ degree air starts pouring out. Never had a problem with other cars even in this heat. Mazda has acknowledged an "engineering" problem with the fan controls (Computerized), however they have still not come up with a fix. Brand new car $30k+ and it's a POS (Piece of>>>). We've contacted a Lemon Law attorney and it sounds like a lot more future "non-Mazda" buyers out there. Just thought I'd share our story to help you make an informed decision. I learned my lesson...stick to Honda products.
  • coachizcoachiz Posts: 9
    My CX9 is less than 3 years old but has 44K miles so I'm out of warranty.
    I did remove the blower motor (under the passenger's dash w/ 3 Torx screws & one connector) & was able to determine the armature is open & very rusted. I have 12VDC at the connector so there doesn't seem to be any additional electrical problems.
    My local Mazda dealer wants $611 for the blower motor over the counter. I was able to find a few aftermarket locations on the web with a $470+ with shipping price tag for the blower. None of the local salvage yards have this part & if they were to get a CX9 in, they would look to sell the entire HVAC unit as opposed to the blower by itself.
    My local dealer didn't want to hear my sob story so they sent me to Mazda Customer Service. Mazda Customer Service (aka Sales Prevention Team) didn't want to hear my sob story either but let me know to keep my receipt for the blower as if there's ever a recall for the problem, I would be reimbursed for the cost of the motor.
    After owning 20+ vehicles over 35 years, I've never had an evaporator drain tube clog. What's even more disturbing is that the vehicle is less than 3 years in service. I believe it's safe to say this is my first & last Mazda vehicle. :lemon: :lemon:
  • wwestwwest Posts: 10,706
    edited August 2011
    "..armature is open and rusted..."

    Rusted: simple sand papering will clear the rust on the "iron" armature surfaces..

    Open: IMMHO that is not very likely. If it uses brushes then the brushes will undoubtedly be stuck in a non-contact position, somewhat retracted position, clean the brush holder(s) and see if the armature is still open.

    Lightly sand papering, cleaning, the copper commutator segments wouldn't hurt.

    If the blower motor uses electronic brushless commutation, as many modern systems do, then I would still clean it up thoroughly and see if now runs. If it doesn't run then the electronic control is most likely at fault.
  • wdhytewdhyte Posts: 92
    We have the 09 GT here in Dallas and its smokin hot this summer (was 112 eysterday on the way to dinner) and have no complaints.
  • davichodavicho Posts: 190
    I learned my lesson...stick to Honda products

    ...even if they look like cr@p!

    2007 Mazda CX-9 Touring 2WD (first generation and first year) with 89,000 miles on the clock. Inland Empire in SoCal every summer temps run between 100-115 degrees...not a single problem. Runs everytime ice cold.
  • coachizcoachiz Posts: 9
    The blower motor is a Denso assembly; it's sealed with no way to repair. Any armature assembly when ohmed out should have some impedence but this one shows open - as if the winding was broken. Got any ideas I'm not aware of?
  • wwestwwest Posts: 10,706
    edited August 2011
    NOTHING is truly sealed.

    what's to lose if you "break" it open.

    "..any armature assembly..."

    No, the brushless ones would likely indicate infinite ohmage since the commutation is done with transistors.

    How did know the armature is rusty...?


    r u near Seattle..?
  • coachizcoachiz Posts: 9
    I purchased the front blower motor online from Their cost was $465 vs. any Mazda dealer I talked to at $611 for the same part. I paid $12 shipping but saved $37 tax. I replaced the blower with the 3 Torx screws, plugged in the connector & everything is fine. A notice to those owners out there who hear a swishing/ water noise under the dash; turn off the AC, check for an evaporator drain hose blockage & don't let the water overflow into the blower motor assembly under the passenger's dashboard. If your passenger's side front mat is wet; you've already overflowed water into the motor assembly & it's just a matter of time before the unit goes. Let's hope Mazda has a recall for this problem so I can get my money back for the motor.
  • wdhytewdhyte Posts: 92
    wouldn't this have been covered under warranty?
  • davichodavicho Posts: 190
    not, if he is out of warranty (time/mileage) or does not have an extended warranty.
  • Where does the evaporator drain hose exit the vehicle? Does anyone have the service repair manuals for the CX9 and does it similar to the Haynes manuals? Thanks
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