We finally got some rain this Saturday while I was in the coupe..I thought the windshield wipers would go on automatically, since I have Rain Sensor.. but they didn't. I turned them on myself. When I checked the manual ( I hadn't checked it before because it never rains here) I found out that you have to turn the knob to the "I" position for the sensor to work, but you can't keep it in that position all the time because the wipers will turn on when you start the car and they can damage the windshield. So what is the point of the Rain Sensor if I can't keep it turned on? Am I missing something here?

 

Hi Margo-

I believe the theory behind the auto-wipers is they adjust the wipe interval based on the amount of rain hitting the windshield (IR signal reflected from the moisture on the glass). I live in Oregon and have had SEVERAL chances to use this feature. I find I still push the button for light mist, guess I am a control freak...

Hope this helps.

 

Haha.. Good point.

But, the rain sensor is for intermitten wiper.
You don't have to change the speed of wiper depands on the amount of rain. It will change the speed by itself like if you slow down or stops for red light, it slows down too.

I hope you understand my bad english....

 

Well, they are assuming that you are more proactive in putting them on, such that when you start to need them, you'll turn them on, which is why it will automatically do an initial swipe when you either turn them on, or start the car with it in the first position.

Honestly, I don't know why people keep bringing this "negative" up. Besides, when I have it in the first position, I think it's a little weird to use the turn signal anyway, so I'd rather have it in the "off" position as much as possible.

 

Margo,
I also have Rain Sensor and was faced with the same question. I thought it would work as an automated feature....but it doesn't.

What R/S really does is calculate the appropriate speed for the intermittant setting according to the amount of distortion created by rain on the upper center section of the windshield glass.

Without this, we'd have an extra knob to control the wiper speed.

(Boy did I feel dumb when the service rep told me this)

 

On a side note, my GF said that she had her wipers on the fastest speed and when she slowed down and stopped at a light, the wipers slowed down to the slower speed.

 

Also, I learned something the other day. When it's misting out (the wipers only wiping once every minute or so), the auto headlights remain off. However, when the rain picks up a bit, the headlights automatically go on. But, the headlights don't go off and on so much as to be annoying. Really cool engineering.

 

I have found that the rain sensor works really well. It adjusts constantly based on how much rain is hitting your windshield. Sometimes it will make two or three regular passes, and then slow down. This is very helpful in traffic when you get a lot of inconsistant "spray" from the other vehicles.

jack230, I agree with you on the lights. I had a Jeep Grand Cherokee before that had this auto light feature, and it drove me crazy. It would constantly turn off and on during dusk/dawn, or when the weather was overcast. The MB seems to have fixed this problem by adjusting the on/off threshold to allow for bigger variances in light.

 

Yeah, I agree completely. Here in the Blue Ridge Mtns I'm always popping in and out of valleys during dawn and dusk and you'd think the lights would go on and off a lot, but nope - they keep it steady either way.

 

On my SL and CLK, I always leave the wipers on intermittent, i.e rain sensors on.

When U start the car, you get one wiper sweep (on a dry windscreen), which I guess does reduce the life of the wiper blade - but who cares ? I just change the wiper blade more, but its not exactly expensive. (I change them about once a year)

 

It also scratches the glass as there's no water to lubricate it.

 

the rain sensor wipers wipe too frequent to my liking.

 

Although I have no complaints to the frequency of the wipes, it would be nice if you could adjust the sensitivity.

 

Well, that hasnt happened to me, but I tend to only keep cars for a couple of years.

 

I've noticed that the wiping frequency is highly dependable of the dirtyness of the windshield/wiper-blade. When they get clogged the wiper starts wiping like crazy, even when the windshield is dry. A gentle spray will solve this problem (for a short while ).

I posted this "problem" a little while ago, and someone told me that the OEM-blades (Bosch) is prone to clogging... I will remember that next time I change.

 

I haven't posted on this subject before, but the programming on these wipers could definitely be better. My $21K 00 GTI-GLX had better programming and sensitivity. If the rain stopped completely so would the wipers-permanently-no single sweeps when the car is started. However, you would have to return the wiper stalk to the off position - then on again if needed after restarting. The sweep rate was also less erratic. The wipers on my 320 seem to get confused-almost possessed at times. I'll admit that its better than having to manually adjust the wipers in relationship to the amount of rain, but having experienced a system that was so effective you didn't have to think about it - leaves me wishing for better programming.

 

If only someone knew how to hack out the software so we can customize our own automatic wiper/light settings...

 

I with you on that

 

I like the way my wipers work just fine. I wouldn't change a thing. I wish I could retrofit this system on my wife's minivan.

The range of opinions on this issue each time it comes up is truly amazing. I guess that's why Mercedes-Benz audience tests these features on a large number of people to arrive at a setting that pleases the most consumers, with an equal number of people on each side that say it either runs too fast or too slow.

Same testing applies to that audio level monitor in the radio system. Some say it compensates too much, others not enough, and the vast majority think it's just fine and never complain about it here.

 

Howdy Folks:
The only complaint I have is that I forget to turn them off, and then I am reminded of my error with that single dry wipe. I would welcome a " reset-to-off " feature whenever the key is turned off.