carpersn

Greetings all; now that i've had my 320 for almost a year, i lurk slightly less around here but have developed an annoying little issue at 12k miles that i wonder if anyone else has?

A couple times a day when turning left or right, my wipers will do one swipe...dry as a bone outside...any news on that-i have not seen a service bulletin, and i have been checking?

Is mine possessed?

HoustonRider

i don't think its coincidence you're using the turn-signals when the wipers do "the mystery swipe". gotta be a slight glitch in the stalk.

I've noticed a few times in auto mode, the wipers have swiped (front and rear) when I put the car in drive.. or even a few times after I've cleaned the windows with glass cleaner after I've started it up. Crazy stuff.

BeanCounter

My father's old Chevy Blazer used to and still does the exact same thing. He took it to the dealer and they told him that they would need to replace the entire stalk on the column to correct the situation (I guess the internal parts start to rub together and set other things off). 100,000 miles later it still does it but everything still works fine. If I remember right it was going to be a pretty pricey repair but since yours is under warranty that will not be an issue. I have not had this issue (yet)..........

StevethePilot

Here's where I've seen the wipers decide to go on their own; both with the Lexus (and Lexus loaners) and the MB's I've driven, when the windsheild gets really hot (I do live in Arizona), sometimes the wipers will go every couple of minutes just when I'm driving down the road. Also, sometimes the slightest moisture will set them off (and then again, sometimes a torrential downpour won't push them to full-on). Something of a trade-off, I guess?

STP

SteveY

I noticed the other day when I set the wipers to automatic, the rear wiper operates the same time the front ones do. Is that suppose to happen in auto mode?

Steve

StevethePilot

To my understanding, that's only supposed to happen when you're in reverse and the front wipers are going. Now, if you have an '08, it might be different or it might be something that has been "programmed" for some reason.

There's a block of coding in the COMAND that can be changed at the dealership and all sorts of things have been added or removed or changed during the production run. This could be one of them thar things!

oknish

My '07 won't do this.

carpersn

I should've pointed out that i am NOT using a turn signal when this happens, only turning the vehicle...my 95 E did this, but obviously didn't have RSWipers which were in the "on" position at the time...

cablvr

I've noticed the same situation on the wife's W221 - although not as frequently. Always attributed the "one swipe" to the sensitivity of the rain sensor (1 drop of moisture, humidity).

blittle

Neither does mine.........

GL Troll

Even without the signal on, turning the wheel though a large angle causes an interaction with the stalk mechanism. It’s what enables it to self cancel the signal.

Why aren’t you signaling?

HoustonRider

my 08, the rear and the front swipe at the same time. not all the time, but if its been raining (or really humid) on start-up they will both swipe a few times.

tbenz

sounds like you may have a defective rain sensor, T-B-82.10/459

JimBarnhart

ok, I'm an electrical engineer with a need to know, how does the rain sensor actually work? I'm thinking it's optical of some sort, but maybe infrared.

DCarrera

I'm interested as well. The speed/rain sensor on my '99 does not always properly detect when it should be in intermitant mode. What I have most of the time on my stalk is

slow-slow-fast not Rsensitive-slow-fast but it does work sometimes and observing the amount of moisture on my windscreen when it does and does not work, indicates it's not the amount of water. I'd have a better chance of predicting normal function with the roll of some 8-side dice.

AsianML

Infrared, iirc.

MB_inspired

It is indeed infrared. Moisture breaks the infrared beams and off the wipers go. The more moisture hitting the beam, the more frequently the wipers swipe.

Note that there is an "adaptation" function that the dealers can perform to the Rainsense wipers if it's wiping too frequently or not frequently enough. This is also supposed to be done if the windshield is changed.

oknish

I have observed the same on my '07 now that it has been raining here in SoCal. I have noticed this only happens if I leave front wipers on when I turm the car off. Then next time when I start the car and front wipers go off sensing rain then the rear one takes a couple of swipes too. IMO, it is probably designed that way but I cannot find anything documented.

blittle

On my 07 the rear wiper never moves unless I turn it on.

oknish

This dang car is smarter than all of us, blittle. I tell ya.