A/C Blower fluctuates and lights dimming

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Hey all,

2018 CX-5 Touring and my A/C blower fluctuates speeds randomly. Also noticed tonight when I turned on my dome light while I was parked, the light dimmed a bit in sync with the blower. At about 16k miles the blower did the same thing but not as bad and they replaced it. This time it seems more frequent and the lights dimming has me more concerned. I did get a new battery recently, but I don’t think it’s that. Currently at 46k miles and hoping nothing serious. Any ideas? Alternator?
 
When the ac compressor cycles in it creates a bit more electrical load but I have never noticed the blower changing speed, but I do usually run the blower on lower speeds to get max dehumidification, never seen lights dim. Since the blower has been replaced once I would favor the blower control switch/circuit with a problem...
 
When the ac compressor cycles in it creates a bit more electrical load but I have never noticed the blower changing speed, but I do usually run the blower on lower speeds to get max dehumidification, never seen lights dim. Since the blower has been replaced once I would favor the blower control switch/circuit with a problem...
Yeah I’m in AZ so have it up higher (not on auto climate control) and it’s definitely fluctuating speeds. The lights I never noticed until today. I pulled out the service report from when it was replaced and it said the motor “resistance was out of spec”. Have an appointment for next week so we’ll see. Hoping I don’t have to pay though since I’m at 46k miles now
 
You can take your vehicle to an auto parts store and have the charging system tested (most of them do this N/C). Then, if that testing shows no problems, I recommend taking it to an auto electric specialty shop for diagnosis and repair (assuming that you cannot or don't want to DIY).

With the BB warranty expired, a stealership is almost certainly going to charge you, and these outfits will typically just start throwing parts. It would be no surprise to me if they replaced the blower motor again, even though IMO it's highly unlikely that the second blower is the underlying problem.

One possible cause that comes to mind is some electrical fault, such as a poor ground, which is causing high resistance in the blower motor circuit, and slowly trashing the motor. But that's nothing but a guess, so knowledgeable testing is what's required to correctly diagnose the problem. And a quality auto electric shop will do that, and likely be able to figure out what the root cause issue is inside of an hour, and get it fixed correctly and permanently on their first try.
 
You can take your vehicle to an auto parts store and have the charging system tested (most of them do this N/C). Then, if that testing shows no problems, I recommend taking it to an auto electric specialty shop for diagnosis and repair (assuming that you cannot or don't want to DIY).

With the BB warranty expired, a stealership is almost certainly going to charge you, and these outfits will typically just start throwing parts. It would be no surprise to me if they replaced the blower motor again, even though IMO it's highly unlikely that the second blower is the underlying problem.

One possible cause that comes to mind is some electrical fault, such as a poor ground, which is causing high resistance in the blower motor circuit, and slowly trashing the motor. But that's nothing but a guess, so knowledgeable testing is what's required to correctly diagnose the problem. And a quality auto electric shop will do that, and likely be able to figure out what the root cause issue is inside of an hour, and get it fixed correctly and permanently on their first try.
Thanks for the recommendations. I’ll get charging system checked…the headlights don’t flicker at all, just inside so not thinking alternator.
I looked at my history and I had CarPlay installed back Jan 2019. When I had the blower replaced was Aug 2019. Any chance when they ripped the dash apart to install CarPlay it could have caused an issue? The service notes said they checked blower motor power and ground before and it was good, but maybe the original cause of first motor acting up was due to something else electrical related like you say.
 
... Any chance when they ripped the dash apart to install CarPlay it could have caused an issue? ....
Definitely a possibility, and IMO that would jump ahead of all the usual suspects. Unfortunately this might make the repair quite a bit more problematic, if the dash has to be ripped apart again. Nevertheless, it still should start with testing at the blower motor circuit, because that's where the problem is showing up.

And, given this new information, I'd urge you to take it to an auto electric shop, tell them about the blower and the CarPlay installation, and ask for their opinion of how to proceed. Most of these auto electric guys are very good at what they do, and are likely to have a much better approach to a problem like this than a regular shop would.
 
Definitely a possibility, and IMO that would jump ahead of all the usual suspects. Unfortunately this might make the repair quite a bit more problematic, if the dash has to be ripped apart again. Nevertheless, it still should start with testing at the blower motor circuit, because that's where the problem is showing up.

And, given this new information, I'd urge you to take it to an auto electric shop, tell them about the blower and the CarPlay installation, and ask for their opinion of how to proceed. Most of these auto electric guys are very good at what they do, and are likely to have a much better approach to a problem like this than a regular shop would.
Thanks again, appreciate the insight. I have a free oil change at stealership so I’ll see what they come up with. I found an auto electric shop in the area that looks good, so I’ll try to visit them as well especially if Mazda can’t come up with a good solution. It’s just frustrating…I want to like the car but between this and having to redo timing cover seal 2x I’m getting tired of going to dealership for work.
 
.... I found an auto electric shop in the area that looks good, so I’ll try to visit them as well especially if Mazda can’t come up with a good solution. ...

Why not try that auto electric shop first? I don't think they would charge you anything to listen to your brief story, and would probably give some advice at N/C as well. Then you can use your gut feel, based on what they say (and how they say it) to decide how to proceed.

I'd really have so much more confidence in this type of shop, and would prefer to hear what they have to say first. And when I read you next comments below, it reinforced this so much more, because there should never be a '2x'. Yes, anyone can make a mistake on a gasket job, but even just a half way competent shop is never going to let it go out the door and back to the owner in that condition.

.... It’s just frustrating…I want to like the car but between this and having to redo timing cover seal 2x I’m getting tired of going to dealership for work.
 
Why not try that auto electric shop first? I don't think they would charge you anything to listen to your brief story, and would probably give some advice at N/C as well. Then you can use your gut feel, based on what they say (and how they say it) to decide how to proceed.

I'd really have so much more confidence in this type of shop, and would prefer to hear what they have to say first. And when I read you next comments below, it reinforced this so much more, because there should never be a '2x'. Yes, anyone can make a mistake on a gasket job, but even just a half way competent shop is never going to let it go out the door and back to the owner in that condition.
Yeah I’m going to try to during the week. It’s hard because auto electric shop only open weekdays and it’s hard for me to get there in time due to work. Agreed, anything 2x should not be the case. Supposedly master mech didn’t do it the first time and there was an issue. I usually only go to dealership while under warranty, then try to take it to local shops that I know won’t try to screw me around
 
.. Supposedly master mech didn’t do it the first time and there was an issue. ...
Yep, the stealerships are great at making excuses, because that's one thing they get to do a lot of.

Good luck getting this problem resolved. And if it turns out that there was some glaring mistake made on the CarPlay install, you could go after them for compensation on the subsequent repairs you've had to make (assuming they're still in business).
 
wth is an "auto electric shop?"
Nowadays it's any shop that specializes in the diagnosis and repair of automotive electrical/electronic problems. That doesn't mean they can't or wont do other auto work as well, but an auto electric shop will usually advertise this specialty, and will actively seek out those types of problems (which many other shops don't want anything to do with). A number of years ago, auto electric shops would also do quite a bit of starter/alternator rebuilding, but I don't think nearly as much of that stuff is happening these days.
 
Yep, the stealerships are great at making excuses, because that's one thing they get to do a lot of.

Good luck getting this problem resolved. And if it turns out that there was some glaring mistake made on the CarPlay install, you could go after them for compensation on the subsequent repairs you've had to make (assuming they're still in business).
Nowadays it's any shop that specializes in the diagnosis and repair of automotive electrical/electronic problems. That doesn't mean they can't or wont do other auto work as well, but an auto electric shop will usually advertise this specialty, and will actively seek out those types of problems (which many other shops don't want anything to do with). A number of years ago, auto electric shops would also do quite a bit of starter/alternator rebuilding, but I don't think nearly as much of that stuff is happening these days.
Yeah the one I found near me specializes in AC and electric but looks like they do other maintenance.
 
Update, I’m done going to dealership especially since I have 46k on the car. Take it in and they say to me “on the weekends we don’t have enough techs to look at the motor”. Also said that if it wasn’t related to CarPlay install issues that I’d have to pay for it because it’s not under warranty. Although my appointment was for an oil change (because I had a free one) you think they’d say something when I told them I needed the motor checked when I made the appointment.
I never had a chance to take it to the local shop this week, but going to do that maybe next week if I’m able to during the week.
 
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