AC Fan Blower sometimes not working

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2022 2.5GT
Modern heaters don’t work with the same “ram air” effect as the old designs did and with the blower fan off, virtually no air will find it’s way through the cabin filter and the labyrinth of passageways into the car. For that reason, the fan is blowing constantly the whole time the car is running. They’re not brushless motors, they are conventional brushed motors and they have a lifespan. It’s amazing how many owners interfere with the settings when all they need to do is set a comfortable temperature and leave it in “auto” and the computer will do the rest including set it back to idle when not needed. That’s instead of roaring away to no good end and reducing the life of the motor. When a motor goes on the blink, it’s invariably the brushes which lose tension and start to stick as they wear out. I tend to pull them to bits and put new brushes in but other than that it’s not that expensive and only about 20 minutes to change the motor which sits inverted above the passengers feet. Finding a fault is easy if it’s displaying it but if you take a working fan into a dealer it’s bloody awkward to find other than tapping things and wriggling wiring connections so it’s easy to be critical about it. If it doesn’t work, plugging a new fan or measuring voltage at the fan plug takes a few seconds. If there’s juice it’s the fan, if there isn’t it’s the control system (usually the control module). As always the conspiracy theories pop up - “there’s more to this than meets the eye” or “mazda are hiding something”. There isn’t. It’s a fan that never stops working from the day the car rolls out of the dealership and when you consider how many millions of cubic feet of air it pumps over several years, it’s amazing it lasts as long as it does. Well done to the OP for taking a punt on the $120 fan, it’s the bit with moving parts and the control unit is solid state so it’s where I’d start every time. For everyone else, if your car is over about 3-5 years, that’s where I’d start on yours too. That little motor has got wearing parts in it.
 

ltcgs12

Member
:
CX-5 Touring
Modern heaters don’t work with the same “ram air” effect as the old designs did and with the blower fan off, virtually no air will find it’s way through the cabin filter and the labyrinth of passageways into the car. For that reason, the fan is blowing constantly the whole time the car is running. They’re not brushless motors, they are conventional brushed motors and they have a lifespan. It’s amazing how many owners interfere with the settings when all they need to do is set a comfortable temperature and leave it in “auto” and the computer will do the rest including set it back to idle when not needed. That’s instead of roaring away to no good end and reducing the life of the motor. When a motor goes on the blink, it’s invariably the brushes which lose tension and start to stick as they wear out. I tend to pull them to bits and put new brushes in but other than that it’s not that expensive and only about 20 minutes to change the motor which sits inverted above the passengers feet. Finding a fault is easy if it’s displaying it but if you take a working fan into a dealer it’s bloody awkward to find other than tapping things and wriggling wiring connections so it’s easy to be critical about it. If it doesn’t work, plugging a new fan or measuring voltage at the fan plug takes a few seconds. If there’s juice it’s the fan, if there isn’t it’s the control system (usually the control module). As always the conspiracy theories pop up - “there’s more to this than meets the eye” or “mazda are hiding something”. There isn’t. It’s a fan that never stops working from the day the car rolls out of the dealership and when you consider how many millions of cubic feet of air it pumps over several years, it’s amazing it lasts as long as it does. Well done to the OP for taking a punt on the $120 fan, it’s the bit with moving parts and the control unit is solid state so it’s where I’d start every time. For everyone else, if your car is over about 3-5 years, that’s where I’d start on yours too. That little motor has got wearing parts in it.
Anchorman, you say "It’s amazing how many owners interfere with the settings when all they need to do is set a comfortable temperature and leave it in “auto” and the computer will do the rest including set it back to idle when not needed. That’s instead of roaring away to no good end and reducing the life of the motor." I think this is like saying don't power your windows down and up because eventually over time that motor will wear out. But I will try your suggestion of using the Auto.
 
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2022 2.5GT
Anchorman, you say "It’s amazing how many owners interfere with the settings when all they need to do is set a comfortable temperature and leave it in “auto” and the computer will do the rest including set it back to idle when not needed. That’s instead of roaring away to no good end and reducing the life of the motor." I think this is like saying don't power your windows down and up because eventually over time that motor will wear out. But I will try your suggestion of using the Auto.
Well not really the same because window motors are very intermittent use ;-). The thing is with the auto setting is that it is completely automatic. When you start on a cold morning you’ll think it isn’t working but it is waiting for the engine to warm up because it knows the only air it can give is going to cool the interior even more. As the engine temp rises, you’ll hear the fan speed increasing until it is going full tilt to get the temperature up to your setting. It’s when the owners often intervene but the algorithms are all programmed and it can’t be beaten. Now let’s say it’s spring or autumn where it’s cold first thing but really warm in the day, it will change from heating to cooling. It can sense sunlight and it can sense humidity and will make adjustments accordingly. It’s very good but you’ve got to trust it. Give it a go and you’ll have fun watching it make all the adjustments. Leave the centre vents partially open and on a long drive it will divert cooler air to your face to stop you getting drowsy. It’s actually a very expensive part to include but unfortunately it’s often overridden so can’t do it’s job. Might just as well have the old on/off switch.
 
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Southwest Ohio
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'19 CX-5 diesel
@ltcgs12 to me, there is no way you've had 4 "bad" blower motors in a row. Something is killing them, dealer tech is misdiagnosing the problem or ???? I can't agree with @Anchorman theory of user intervention of HVAC control as a cause of multiple blower motor failures in such a short time. Something else is wrong (IMHO).
 
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2022 2.5GT
@ltcgs12 to me, there is no way you've had 4 "bad" blower motors in a row. Something is killing them, dealer tech is misdiagnosing the problem or ???? I can't agree with @Anchorman theory of user intervention of HVAC control as a cause of multiple blower motor failures in such a short time. Something else is wrong (IMHO).
We’re missing part of the story with that one. The original complaint is poor heater performance and there’s no way even running a fan full speed would burn them out so frequently. I run the UK CX-5 Facebook group and we’ve never had a report of a fan going and the first one here is quite unusual. I know if the cabin filter is blocked it will starve the motor of cooling air so I’d need a little poke around to understand that one better. Something isn’t right 😉
 
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Pueblo county CO
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CX-5 Sport 16.5 6M
Electric motors are such simple devices. The only parts that wear are the brushes and bearings. It takes a lot of heat or a major overload to fry the windings.

Are they just throwing parts at it?
 
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2017 CX-5 Sport
I replaced my blower motor last week, by far it was the easiest part I've ever replaced on a car (other than light bulbs on previous cars), 3 screws and a plug. It only cost me about 100 for the part on Rock Auto.
 
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2022 2.5GT
I replaced my blower motor last week, by far it was the easiest part I've ever replaced on a car (other than light bulbs on previous cars), 3 screws and a plug. It only cost me about 100 for the part on Rock Auto.
It’s a japanese idea that many others have followed. The motor used to be right inside the heater and the heater is right inside the dashboard so it was hours of a job to get at the only potentially wearing part. Just moving it over to the passenger footwell was the most radical change and also provided a home for a cabin filter. Incidentally, the most suspect part of the motor are the brushes. I used to make them out of carbon and they’d last years.
 

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