Wipers with a mind of their own

[TBarney]

Picked up a '17 GT w/ Prem Package a few weeks ago and am still figuring things out, but I think I've got an actual problem here, wondering if anyone else has seen it and possibly has a resolution:

First couple of weeks I had the car, wipers were set to "Rain Sensing = ON" and they worked OK. This is the second car we've had with this feature, and I usually get irritated after a while because they never seem to find the sweet spot. I did notice that they didn't really seem to respond to the sensitivity dial.

Doing some reading here, I figured out that Rain Sensing can be turned OFF, and they'll work like regular intermittent wipers. So the last good rain, I did that.

And that's when the problems started. The wipers now go off randomly. Here are the things I've witnessed:
- Bump the stalk up for single wipe, and the wipers swipe 2-3 times.
- Turn the wipers to Intermittent, on the slowest setting, and the wipers swipe 2-3 times, then pause for a while, then swipe once, then pause for a different period of time, then swipe a couple of times, then pause...it's very random and not at all in any kind of steady rate.
- Twisting the dial for a faster period doesn't seem to change anything.
- Turn the wipers OFF (yes, I'm sure it was the off position) and the wipers swipe 2 times, pause, swipe another 2-3 times, then finally quit.
- Started the car after it sat all day at work, wipers OFF (dry windshield) and the wipers swipe 2 times then stop.
- Been dry since then and the wipers have stayed OFF the last couple of times I've driven.

Don't know if I've got a bad switch, or a bad control unit (FBCU? RBCU?) or some other element. It's not clear to me from the wiring diagrams just where this problem is likely to originate.

I'm out of bumper-to-bumper warranty, so I'll pay for this repair, but I'd rather have some idea what it's going to be, if possible.

I'm really hoping there's just some kind of reset I can do, but I don't know that would be...

Help?

 

[yrwei52]

Picked up a '17 GT w/ Prem Package a few weeks ago and am still figuring things out, but I think I've got an actual problem here, wondering if anyone else has seen it and possibly has a resolution:

First couple of weeks I had the car, wipers were set to "Rain Sensing = ON" and they worked OK. This is the second car we've had with this feature, and I usually get irritated after a while because they never seem to find the sweet spot. I did notice that they didn't really seem to respond to the sensitivity dial.

Doing some reading here, I figured out that Rain Sensing can be turned OFF, and they'll work like regular intermittent wipers. So the last good rain, I did that.

And that's when the problems started. The wipers now go off randomly. Here are the things I've witnessed:
- Bump the stalk up for single wipe, and the wipers swipe 2-3 times.
- Turn the wipers to Intermittent, on the slowest setting, and the wipers swipe 2-3 times, then pause for a while, then swipe once, then pause for a different period of time, then swipe a couple of times, then pause...it's very random and not at all in any kind of steady rate.
- Twisting the dial for a faster period doesn't seem to change anything.
- Turn the wipers OFF (yes, I'm sure it was the off position) and the wipers swipe 2 times, pause, swipe another 2-3 times, then finally quit.
- Started the car after it sat all day at work, wipers OFF (dry windshield) and the wipers swipe 2 times then stop.
- Been dry since then and the wipers have stayed OFF the last couple of times I've driven.

Don't know if I've got a bad switch, or a bad control unit (FBCU? RBCU?) or some other element. It's not clear to me from the wiring diagrams just where this problem is likely to originate.

I'm out of bumper-to-bumper warranty, so I'll pay for this repair, but I'd rather have some idea what it's going to be, if possible.

I'm really hoping there's just some kind of reset I can do, but I don't know that would be...

Help?

I’d try to switch the rain-sensing feature back on and see, or turn the feature on and off several times with ignition ON without engine running. Also, find out if the windshield had been replaced if there’s any service records you can trace, or check the imprint mark on the lower driver side and see if there’s Mazda logo in it. You may try to remove negative battery post for a “reset”. If everything fails, I’d just set the rain-sensing feature on and hopefully it’d behave like before you did setup change.

 

[TWILE]

Was this ever solved? I am having the same issue with my 22 CX9

 

[ruthrj]

Was this ever solved? I am having the same issue with my 22 CX9

Random activation of the wipers like the original post, or is your issue isolated to only when the rain sensing feature is on? Sorry, original post was hard to pin down for me.

Describe what you’ve got going on and let’s see if folks chime in. My mother in laws light/rain sensor fell off the windshield and the rain sensing feature of the wipers wouldn’t work. I tried fixing the sensor but half of it didn’t stick well to the glass. That caused the wipers to work furiously. I turned off rain sensing to make it perform like traditional intermittently timed wipers and moved on.

 

[ceric]

What OP described (I know, it was from 2020) seems like due to a bad switch.

A common issue is condensation inside the housing.
That would cause the sensor to be over-reacting initially until condensation is gone.
This usually happens to mine in winter night when car just got started up (and rain-sensing is on) .... after a few tens of secs, it goes back to normalcy.

 

[TWILE]

Issue started over a year and a half after the windshield was replaced. If I turn the windshield clean function on it sprays the windshield and the wipers won’t turn off. Also if I turn the windshield wipers on high or low and then turn off the windshield wipers, they still continue to run randomly. The only way for me to turn off the windshield wipers to turn off the car.

The dealer is trying to blame it on an aftermarket windshield. The rain sensor was replaced as well as the original aftermarket windshield because the rain sensor bracket wasn’t allowing the rain sensor to sit properly.

So far I’ve gotten a new aftermarket windshield (warranty through safelite) and the dealer replaced the wiper motor, switch, and checked the body control module (which they say is good). They are now trying to come back and say that I need to replace the glass with an OEM glass and that is the issue. It’s clearly something electrical, but they don’t want to pay for the money to diagnose the car even though it’s under warranty.

Car is 2.5 years old with 29k miles on it

 

[HyFlyer]

Note to self .... Insist on OEM glass (or parts for that matter) while under warranty just to eliminate your experience from coming up

Thanks for posting your experience.

 

[ceric]

I replaced the windshield on my '14 Mazda3 with Safelite windshield.
Everything works well. There is rain-sensing on my Mazda3. I tested it.
The technician did test it before he left.

 

[TWILE]

It has nothing to do with the windshield. They can’t trace the issue and that’s their excuse

Any person with half a brain would realize that the wiper function should not be impacted by the automatic rain sensor if the function is turned off in the infotainment which it is. Even after replacing the rain sensor and the original aftermarket windshield, the problem still exists.

Outside of a bad wiring harness I’m lost as to what would cause it

 

[ruthrj]

That’s incredibly frustrating. Disabling rain sensing via infotainment was the only trick I had up my sleeve.

 

[ADS-B]

Have you considered reinstalling the software all together? Just a thought.

 

[TWILE]

The dealer reset the software in the infotainment twice already. They have no explanation for why the windshield wipers keep going after the switch is turned off

 

[TWILE]

the new wiper motor that the dealer replaced was also defective. They replaced it on Friday and the tech drove it all weekend without issue. After a month and a half it looks like I’m finally getting my car back