Odd windscreen wiper behaviour

PeteHr · September 25

A very strange one with my 2 month old Takumi today. Put the key fob in my pocket, opened my kitchen door and noticed the windscreen wipers were going !!! Car was still locked.... Unlocked as usual and then had to turn the wipers off manually. It wasn't even raining and the car was completely dry !! I had been outside 10 minutes before (without the key) and I'm pretty sure the wipers weren't going then...

Anyone else seen such weird behaviour or got any ideas ? Many thanks !

Don C · September 25

I mostly wax lyrical about Lexus and Toyota. I’m very confident about Denso products but this Denso auto wiper system that both brands use really sucks - it’s garbage. Having said that, the feed is hooked into the front body control module and it shouldn’t be possible to start after you’ve parked it. It can before you shut it off so just check there’s nothing obscuring the screen on the outside of the sensor. The sensor is the oblong plastic thing right next to the plastic cover by the mirror housing. If the top of the screen is perfectly clean then you’ll have to take it to the dealer. There is one other possibility - has it had a dashcam by any chance?

PeteHr · September 26

17 hours ago, Don C said:

I mostly wax lyrical about Lexus and Toyota. I’m very confident about Denso products but this Denso auto wiper system that both brands use really sucks - it’s garbage. Having said that, the feed is hooked into the front body control module and it shouldn’t be possible to start after you’ve parked it. It can before you shut it off so just check there’s nothing obscuring the screen on the outside of the sensor. The sensor is the oblong plastic thing right next to the plastic cover by the mirror housing. If the top of the screen is perfectly clean then you’ll have to take it to the dealer. There is one other possibility - has it had a dashcam by any chance?

Thanks for your reply Don ! I don't have a dash cam and the screen is completely clean. What I don't understand is that just approaching the car with the key in my pocket, without even going to unlock the car, seems to have started the wipers ! I guess it's another thing I need to get the dealer to look at when I take it in. I'm saving all the niggles up as I'm hoping to get everything sorted when I take it in for the recall !

Don C · September 26

55 minutes ago, PeteHr said:

Thanks for your reply Don ! I don't have a dash cam and the screen is completely clean. What I don't understand is that just approaching the car with the key in my pocket, without even going to unlock the car, seems to have started the wipers ! I guess it's another thing I need to get the dealer to look at when I take it in. I'm saving all the niggles up as I'm hoping to get everything sorted when I take it in for the recall !

Approaching the car does wake it up - the interior lighting comes on etc but it must be picking a feed up. It’ll get the Lexus guys scratching their heads.

NemesisUK · September 26

You say you had to turn off the wipers, so you had left them on Auto when you switched off and locked the car? On Mercedes with auto wipers they would always wipe once the IGN was switched on to show they were set to Auto. Could it be similar, except as the car 'woke-up' the wipers signalled they were on Auto?

RONNIE W HODGEKINSON · September 26

28 minutes ago, NemesisUK said:

You say you had to turn off the wipers, so you had left them on Auto when you switched off and locked the car? On Mercedes with auto wipers they would always wipe once the IGN was switched on to show they were set to Auto. Could it be similar, except as the car 'woke-up' the wipers signalled they were on Auto?

Yes.. That's the Very Point i was going to Suggest...!!!!

PeteHr · September 26

5 hours ago, NemesisUK said:

You say you had to turn off the wipers, so you had left them on Auto when you switched off and locked the car? On Mercedes with auto wipers they would always wipe once the IGN was switched on to show they were set to Auto. Could it be similar, except as the car 'woke-up' the wipers signalled they were on Auto?

Hi, yes I'm pretty sure the wipers were set to auto which is how I always have them set. It does seem likely that waking the car up is what triggered them to start - but they have never done this before. Very strange !