New Car, Unknown windscreen sensors W/Photos

[B.holland 0]

Hey,

Ive just upgraded to a 1997 528i and there are a few sensors on the rear-view mirror and the windscreent that are forgein to me, they look like light or rain sensors but either they dont work or i cant find the buttons to turn them on lol.

Please help me ID what they are and how to use them.

Thanks.

[Ahmedsinc 414]

Jap import? Fairly sure they're IR(?) receivers for your keyless entry

then again, I'm no expert

[tmase 19]

The sensor/photo cell on the reflective face of the mirror and on the opposite side are probably for the auto dimming function, so that following traffic doesn't blind you with their headlights at night. The one against the windscreen pane below the rear vision mirror is for the rain sensing wipers on my E39. In there somewhere is the auto head light sensor as well. As stated, the red thing/clown's nose on the is probably the IR sensor for your remote locking if it is a jap import, though it could be an alarm indicator light if you have an RF key.

Instructions from my MY02 owners manual (your MY97 could be different):

To activate rain sensor place the wiper stalk in the intermittent position, wipers will travel across the screen once. You can leave the lever in intermittent all the time, then all you need to do is turn the knurled wheel on the stalk once to activate rain sensing. The knurled wheel is seven settings that vary the sensitivity of the rain sensor.

Auto lights are activated by switching the headlight selector anti-clockwise from off to the (A) position. Low beam headlights are switched on and off automatically depending on ambient light conditions.

The auto dimming mirrors sometimes leak a fluid from them which stops them from working. There might be a change in tint separated by a horizontal line on the face of the mirror if this is happened. I understand they are expensive to replace, but you can get non dimming ones much cheaper. Looking at the pictures though I doubt that's happened.

[B.holland 0]

Hey,

You were spot on with the rain sensor. I flicked it to intermittent and sprayed with the hose and BINGO ! It worked.

But my dash/lights cluster don't have an A on them so not sure if I have the light sensor or how to use it

The rearview mirror oil is still intact but it hasn't dimmed yet, unless it's doing it without me knowing lol. There is an on off position on my clown nose but nothing changes when I turn it off vs being on. Unless it only works if high beams are shining on it. I haven't been able to test it with high beams yet....

Massive thanks for the info on the rain sensor. The previous owner didn't even know that feature was on the car. This makes my purchase even better value

Thanks

[tmase 19]

Auto lights might have been an option in 97 maybe?

The dimming mirrors develop a greenish tint when they dim, your wing mirrors might also do it too. I think the system measures the the amount of light hitting the forward facing photo cell, and when it determines that it is dark enough it will dim the mirror when a bright light source hits the reflective side. So yeah really only noticeable in the dark.

Not sure what the on/off switch is for, my car doesn't have it and no mention of it my owners manual.

BTW if you ever get your windscreen replaced make sure there are no bubbles trapped between the glass and the sealant over the sensor, otherwise it won't work. BMW dealerships change out the sensor at the same time the glass is changed but as this is expensive most insurance companies won't run to that expense and reuse the old sensor.

Edited April 14, 2013 by tmase

[Allanw 1072]

Auto lights were only for facelift E39's I think??? and even then may have only been the later ones (02 on???)

[tmase 19]

You may find http://e38.org/2000Manual-5Sedan-SportWagon.pdf useful, it is for the US market and is for a 2000 model year, but it is the earliest I could see.

[B.holland 0]

Mines a 97 but yeah I can't see any auto feature anywhere to do with lights. The confusing part is the on off for my clown nose. Can't figure out what it does lol. And I haven't seen the night rearview mirror do its thing either. But haven't tested with high beam shining on it. And as for my side mirrors they are a blue colour which seems odd.

[beemn 50]

Mines a 97 but yeah I can't see any auto feature anywhere to do with lights. The confusing part is the on off for my clown nose. Can't figure out what it does lol. And I haven't seen the night rearview mirror do its thing either. But haven't tested with high beam shining on it. And as for my side mirrors they are a blue colour which seems odd.

Auto lights are only on late models, 02 onward for the e39 (Fairly sure), the on off on the mirror is to turn on and off the auto dimming, had it on a previous car dont remember which one though you can normally see the green tint at night if you turn on the interior lights

Edited April 15, 2013 by beemn

[KwS 2429]

to test the auto dimming mirror, use your hand to block the sensor on the windscreen side (your 3rd picture) and then shine a bright torch into the dot on the glass as seen in picture two. If its working it should change to a tinted green, and change back when torch light is removed.

[jochen 4]

First and Last Photo: rain sensor for auto wipers. Also is the light sensor for auto headlights

Third Photo: oncoming light sensor for auto-dimming rear view mirror 8and also for auto-dimming external mirrors, if fitted)

Second photo: unknown. Likely some jap add-on.