How can I tell if I have a rain sensor? - PeachParts Mercedes-Benz Forum

Graplr · #1 02-08-2011, 05:28 PM

I have a crack in my windshield and it is getting replaced on Thursday (covered under insurance). They asked my if I have a rain sensor. I'm still trying to figure out lots of things on my wagon as I've only had it a month. I'm assuming it does.
Thanks!
Ryan

compu_85 · #2 02-08-2011, 06:19 PM

Do your wipers come on when it rains? From outside the car look at the rear view mirror. Is there a lens siliconed to the glass?

-J

Graplr · #3 02-08-2011, 07:09 PM

Quote:

Originally Posted by compu_85

Do your wipers come on when it rains? From outside the car look at the rear view mirror. Is there a lens siliconed to the glass?

-J

It hasn't rained since I've owned it...only snow.

Not sure if that makes a difference or not. I'll check the rear view mirror.

greenacres2 · #4 02-08-2011, 08:16 PM

The switch would be a clue also--mine is a three position with no adjustment for the intermittent setting since it is self-adjusting with the sensor.

04 Diesel · #5 02-08-2011, 09:19 PM

Turn car on and spray with hose and you will see.

Graplr · #6 02-08-2011, 09:43 PM

Quote:

Originally Posted by 04 Diesel

Turn car on and spray with hose and you will see.

A bit hard to do that now since it is -5F out.

Graplr · #7 02-08-2011, 09:48 PM

Quote:

Originally Posted by greenacres2

The switch would be a clue also--mine is a three position with no adjustment for the intermittent setting since it is self-adjusting with the sensor.

I did notice that I have no delay on the first position. The first position is the same as the second with the third being fast. But my SD was the same so I guess I didn't know there was an adjustment on Mercedes. Although my wipers don't come on in the car wash so that makes me think I don't have the rain sensor.

greenacres2 · #8 02-09-2011, 07:12 AM

On mine...
OFF is off--no matter how much water (i.e. car wash)
I position is self-sensing intermittent--initial wipe, then as needed
II position is low speed constant
III position is high speed constant
Light push-in on end of stalk is single swipe, heavier push-in is washer.

My system has 2 relays--Wiper On/Off and Wiper I/II. Don't know how the electricity works, but IF you have the sensor spot on the windshield but no variable speed, one of the relays may be out. They're about $5-$6 on fast lane, and it's a relay that fits multiple locations.

We're at 2 above here this morning--all the water is solid. Good luck.

Aquaticedge · #9 02-09-2011, 08:10 AM

would throwing a couple buckets of water Trigger it? (please make sure it's not hot water or another temp that would break glass!)

Ferdman · #10 02-09-2011, 08:44 AM

Ryan, I suspect if you call your local MB dealer with your VIN they can tell you what options are on your vehicle. Or stop by your local MB dealer and have a tech look at your wagon.

Any knowledgeable windshield replacement vendor should recognize and reinstall the rain sensor.

RichardM98 · #11 02-09-2011, 08:46 AM

You don't need to throw water on it. The rain sensor is easily visible from the outside. In the center of the windshield about 2-3" down from the trim you can see a purple-blue irridescient spot. That is the rain sensor if you have one. Also if you look on the inside of the windshield in the same spot you will see a small black plastic box which is the cover for the rain sensor.

TX76513 · #12 02-09-2011, 08:47 AM

Quote:

Originally Posted by RichardM98

You don't need to throw water on it. The rain sensor is easily visible from the outside. In the center of the windshield about 2-3" down from the trim you can see a purple-blue irridescient spot. That is the rain sensor if you have one. Also if you look on the inside of the windshield in the same spot you will see a small black plastic box which is the cover for the rain sensor.

Correct - test by taking a piece of wax paper and covering it with the switch in the auto position.

Graplr · #13 02-09-2011, 09:27 AM

Quote:

Originally Posted by Ferdman

Ryan, I suspect if you call your local MB dealer with your VIN they can tell you what options are on your vehicle. Or stop by your local MB dealer and have a tech look at your wagon.

Any knowledgeable windshield replacement vendor should recognize and reinstall the rain sensor.

That would be the simplest solution now wouldn't it?

Graplr · #14 02-09-2011, 09:29 AM

Quote:

Originally Posted by RichardM98

You don't need to throw water on it. The rain sensor is easily visible from the outside. In the center of the windshield about 2-3" down from the trim you can see a purple-blue irridescient spot. That is the rain sensor if you have one. Also if you look on the inside of the windshield in the same spot you will see a small black plastic box which is the cover for the rain sensor.

I'm positive I have the black box on the inside. But I did not see any "spot" on the outside. I am color-blind and it was not very well lit when I was looking so that may be the issue.

Right now it sounds like I have a rain sensor that is not working properly as when I turn it into position I the wipers run constantly no matter if the windshield is dry or damp.

compu_85 · #15 02-09-2011, 11:22 AM

Take a picture of the box from the outside.

-J

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