rshoemaker

What would cause the intermittent setting on my wipers to only work intermittently? Sometimes when it is raining very lightly, the wipers work as expected when set on intermittent, but mostly they go back and forth constantly as if on the low setting.

raymond g-

Rain sensing option (grid on windshield top center-behind rear view mirror): "...When the rain sensor detected water droplets on the windshield, it would activate the wipers for a single sweep, then check again. If the sensor "saw" more drops, the wipers took another sweep. In heavy rain, they swept continuously."

Is yours working in contrary fashion?

rshoemaker

I'm saying that there is essentially no difference between the intermittent setting and the low setting. Even when it is barely raining at all, the wipers sweep back and forth continuously on the low setting. Every once in awhile the intermittent setting actually works and the wipers hesitate between sweeps.

bingoldsby

Can someone please explain just how the rain sensor works. Mine works perfectly, but it's a curiosity to me as to how.

Thanks,

Brian - Yakima, WA
2000 E320

raymond g-

i dont have one on my 99, but my brother's 2000 is sitting in the driveway and
my experience is this: the metalized grid embedded into the top of the wind-
shield (level with the inside rear view mirror) is the wetness detect. On first
click of the switch, if rain sensor senses rain, it swipes. If not, it delays until
rain accumulates on sensor and it deploys again - swipe/swipe.

bingoldsby

Raymond,

Go inside the car and feel the windshield at the area of the "grid" around the mirror. You will feel that it is something applied to the glass on the inside and in my estimation has nothing to do with rain sensing. I do see from the outside a little patch of blue in that area but can't get close enough with out climbing on the hood to get a good look at it. Perhaps that has something to do with it.

It's a mystery to me - still - but sure works well.

Brian

Whitey

The round blue thing in the grid IS the sensor, not the grid itself. When it senses rain on it (presumably if its blocked), it tells the wipers to swipe. Pour some water over it with one click of the lever and you will see. Never tried putting something solid over it although I'm guessing it'll work too....but its not a good idea to activate the wipers without any liquid whatsoever so I'm not prepared to try.

rshoemaker, when u say "when it is barely raining", is the rain continuous or are you talking about drizzles? If it is light rain (a little more than drizzles), the sensor will still cause the wiper to work like it is on low, even tho it is set on intermittent. When the car is stationery (e.g. at the lights), the wipers should go back to normal intermittent operation under these conditions.

raymond g-

LOL...I didn't pay close enough attention to that. When brought up last year
on this board, someone else said it was the grid and I just took their word for
it. Wasn't curious enough to examine close up or climb the hood like Lt Columbo
would have, neither. Thx for the correction...B and W.

rshoemaker

When I say "barely raining", I mean the kind of rain where you think you might have felt a drop of water, so you stick your hand out and look up at the sky. Light enough that the drops on the windshield almost disappear so fast that you don't need the wipers on at all. Under those conditions, I would expect the wipers to run intermittently, but they run as if set on the continuous low setting (most of the time). They do occasionally work the way I would expect.

Maybe I should throw a new wiper blade on there and see if that make a difference. Perhaps the blade is leaving a stream of water in front of the sensor or something...

Potterer

I am experiencing a similar problem - even in a dry weather situation I find if switching wipers on to "slow wipe function" they give one or maybe two delayed sweeps then start to operate continually at a slightly higher frequency than the normal speed. Same situation when switched to the "reduced time delay function" ( apologies for using my own descriptions, not sure how else to describe that I have two speed options, allegedly , on the wiper function switch). I am confident that my wiper blades are perfectly clean and undamaged and that the windscreen area over the rain sensor is equally pristine. Guess the problem lies within the actual sensor but not sure yet if this can be reset by the MB garage or it will need replacing. Will post my findings after a visit to the garage - no doubt after leaving them with a not inconsiderable contribution of my hard earned cash.