e class rain sensor unit

[fraser5002]

hi,
i managed to get myself a rain sensor off of ebay from an E class and im going to custom it to fit my merc which does not have one, however i dont really have a clue what the connections on it are there are 3 pins, anyone know which is which, i assume one is +v one is ground but what is the other. Anyone fitted one of these before or has knowledge of them?
thanks
Fraser

part number is A 211 870 29 26 if that helps any.

 

[television]

The other should be the one for operating the wiper, I will see if I can find something on it.

malcolm

 

[jberks]

Do you have the gap in the blacked out area at the top of your windscreen to fit one? I though the screens were different so if not and you fit it where it should go, it will be blind.

 

[fraser5002]

oh right didnt know that i thought i could just be placed anywhere on the window, doh ! ah well only 2 quid on ebay so no big loss, what does the blacked out bit do, is it a polariser or something?

 

[jberks]

I think its just to stop glare, so they block out areas that are no use anyway, such as round the back of the mirror. The problem is that you need to mount the sensor somewhere that it can see out, that is wiped by the wiper but at the same time, doesn't obscure your view by being stuck there (or as well as being a bid idea, it it could fail your mot). So, your options are limited. This is why they mount it behind the mirror. The wiper passes it, but you don't look out.
You may be able to scrape away the blacking out material to make a small square in the right place though. I believe its just painted on.

 

[Blobcat]

Assuming RHD, you could mount it to the left of the blacked out area but still behind the mirror from the drivers point of view. This is still in the swept area for the wiper so it would still work correctly. Or you could replace the screen with one which has the gap for the sensor, if your screen is damaged..

 

[television]

It could be fitted anywhere on the screen,within the arc of the wiper, out of sight by the driver such as tax disc area,but on the drivers side. Rain hits the screen anywhere, the sensor works by the rain drop reflecting back onto the sensor.

Malcolm

 

[pcman_jh]

Auto rain sensor - missing an important point

I had my windscreen replaced about a month ago due to a crack, so know all about rain sensors!

You can't simply stick the black box onto the windscreen - or to put it more specifically - you'd be better gluing an empty cardboard box as it still wouldn't work. This is becasue you need the windscreen to have a special pad attached to it which the rain sensor then clicks onto. This specially glued on pad then allows the optical sensors in the black box to detect water. Without the special pad already glued to your windscreen, you're barking up the wrong tree!

 

[jberks]

Interesting point. What does the pad do that attaching it directly wouldn't? Does it blank out the unwanted light, have an integral lens or ...?

 

[television]

Interesting point. What does the pad do that attaching it directly wouldn't? Does it blank out the unwanted light, have an integral lens or ...?

Just been down to look at mine,and it looks like a lens.

Malcolm

 

[fraser5002]

ok cheers for your help guys, dont have any of these pads or anything your talking about haha so i think the project is doomed if anyones rain sensor decides to chuck it one day you know where to come haha !

 

[television]

One of the best thing on this site is that some of these things do make you think. Not being happy with what I was looking at earlier , and I thought it was a lens, its not,went into the garage in the dark and turned on wiper, at is a type of vari cap, as used to be used,on early TV's and still used on some B & O systems, it will work with just your finger over the sensors, signals can be passed through glass. there used to be coax connection where you put one connector each side and the signal passed through. never tried them though. Big trouble for me is that I do not sleep until solved.
Its a nice feature to have though.

Malcolm

 

[fraser5002]

does anyone know which pin is which anyway? like i said there are 3 pins on the sensor +v , gnd and motor connection im assuming but which is which, im determined to have a go at this haha, see what happens.