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The truth about rain and light sensors/auto headlights

34K views 20 replies 16 participants last post by  austinadrew11 
#1 ·
Bimmer Jon and I have been working together to figure out how you retrofit auto headlights into a 2001 or older e46. Through our research we have discovered the following:

Prior to 9/2001 you could buy auto rain wipers, which sense how much rain is falling and regulate your windshield wiper speeds accordingly. You can tell if you have a rain sensor equipped car by looking at the top middle of the windscreen and if it's equipped with this rain sensor it looks like this:



Subsequent to 9/2001 BMW added an auto headlight feature, which turns your headlights on when it's dark and off when it's light. These cars are equipped with a rain and light sensor, which is different than just a rain sensor, and a light control module with an automatic headlight setting. The difference can be seen here (item number 1): http://www.realoem.com/bmw/showparts.do?model=AV53&mospid=47725&btnr=61_0169&hg=61&fg=15&hl=7

The wiring and connectors are the same for both.

The electronic box that feeds these signals to the Light Control Module is attached to the window with two clips, with slight differences between the rain sensor and the rain and light sensor. What makes it impractical to just change out the sensor is the fact that the receptors are glued to the windshield, and are not interchangeable. The rain sensor looks like this:



The rain and light sensor looks like this:



So, your options if you're trying to retrofit auto headlights onto your pre-9/2001 E46 are to unglue the receptor from the windscreen and glue on the new receptor, or to install a windshield with the new receptor attached. After that, it's a matter of installing a new light control module with the auto headlight setting and having the car recoded to work with your new sensors.

At this time, I'm waiting until I get a new windshield, at which time I'll get one with the rain and light sensor receptors.
 
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#6 ·
hey dude. I have an 03/03 M3 and i want to know how to find out if i have the rain sensor? I am very interested in fitting the auto headlight function on the car. Thanks.
 
#10 ·
I think you would also need to change the windscreen.
 
#12 ·
This may be stupid, but they're talking about swapping lights in an e46....you have an e36.......the lights won't fit regardless....


Sorry if you are inquiring about the e46, just noticed you have an e36.
 
#13 · (Edited)
What happened with this? Is the 2001/09 glass (rain + light) and an the auto light LCM all you need?

I am ordering new glass soon. I put in a question to Tischer about this. Hopefully someone knows.

I have an 2001/03 with a Euro LCM I got for coding OEM LED retrofit.
 
#14 · (Edited)
Short answer is yes if you have the wiring harness. See this DIY (and Jaymemaurice's continuation at the bottom) if you don't.

http://forum.e46fanatics.com/showthread.php?t=746918

Edit: You'll also need the plastic housing that surrounds the mirror stalk. It's bigger on cars with the RLS.
 
#15 ·
Hopefully it is OK to kick up this (fairy) old topic. I have a E46 323Ci (EU version, don't know if that matters) and have xenon. I would like to retrofit the auto on feature. Is it correct that i need the sensor behind my rear view mirror? Or is this depleted and old news that i am reading?

Hopefully somebody can clear this up for me :) Thanks!
 
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