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Discussion Starter · #1 ·
Anyone know definitively if the auto headlight conrol feature introduced in MY02 can be retrofit to MY01 by simply swapping the light control module?

My theory is that this feature was added by simply changing the electronics (probably just the firmware) for the LSZ (light module) to use the ambient light sensor, already present to control dimming of the instrument cluster lighting, to activate the headlights. A new switch and front bezel would be necessary too, but this is pretty small potatoes.

In theory, this should be a successful means to add auto lights. After all, the sensor works pretty well to control the dimming of the instrument cluster, which is the same thing really (in reverse).

Dave
 
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dwallersv said:
Anyone know definitively if the auto headlight conrol feature introduced in MY02 can be retrofit to MY01 by simply swapping the light control module?

My theory is that this feature was added by simply changing the electronics (probably just the firmware) for the LSZ (light module) to use the ambient light sensor, already present to control dimming of the instrument cluster lighting, to activate the headlights. A new switch and front bezel would be necessary too, but this is pretty small potatoes.

In theory, this should be a successful means to add auto lights. After all, the sensor works pretty well to control the dimming of the instrument cluster, which is the same thing really (in reverse).

Dave
Why?
 

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King of Rear Clunks
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That system actually uses the same sensor unit as the auto wiper system (that's why they're bundled together). It doesn't use the interior light sensor, so swapping the LSZ alone (it does need to be swapped, too) will likely not work.

And why do you need that stupid old-man feature anyhow?
 

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Discussion Starter · #6 · (Edited)
Kaz said:
And why do you need that stupid old-man feature anyhow?
(Already regretting taking the bait...) It's certainly not a matter of need. If it was, I wouldn't have bout a BMW in '01 -- I would have bought a competitor with the feature.

My Jeep Grand Cherokee had this feature. So does our new minivan. I like it. Not so much that I'd go to any great lengths to add it, but if all that is necessary is a simple swap of the LSZ (piece of cake), and the price wasn't too steep, I'd consider it.

Oh, and did I mention I'm an old man? [40]

Dave
 

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Discussion Starter · #7 ·
Kaz said:
That system actually uses the same sensor unit as the auto wiper system (that's why they're bundled together). It doesn't use the interior light sensor, so swapping the LSZ alone (it does need to be swapped, too) will likely not work.
Are you referring to the rain-sensing wiper sensor?

If so, are you certain of this? I'm skeptical... The rain sensor is an IR based system, and the IR solid-state detectors used are not suitable for gauging overall ambient brightness. I'd appreciate any reference you could provide.

I've asked at my dealership, and the parts guys as well as a couple of mechanics have no idea how the system works.

Dave
 

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fahrer
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alee said:
I thought it used the front facing "reference" sensor in the auto-dimming rear view mirror.

-Al
I believe that's actually for the auto-dimming rearview.

The system takes the difference between light in front of
the car and light from behind in order to determine if the
light from behind is headlights or glare - or something to
that effect. I'm pretty sure it's explained in the BMW
Technology brochure in the glovebox pouch.
 

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bluer1 said:


I believe that's actually for the auto-dimming rearview.

The system takes the difference between light in front of the car and light from behind in order to determine if the light from behind is headlights or glare - or something to that effect. I'm pretty sure it's explained in the BMWtechnology brochure in the glovebox pouch.
I know it's for the auto-dimming, but I believe it may have a dual purpose when coupled with the automatic headlights. The automatic headlights may take that reference point also from that sensor, and maybe an internal sensor as well to determine whether it is dark enough to turn on the lights.
 

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fahrer
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alee said:

I know it's for the auto-dimming, but I believe it may have a dual purpose when coupled with the automatic headlights. The automatic headlights may take that reference point also from that sensor, and maybe an internal sensor as well to determine whether it is dark enough to turn on the lights.
Now I see what you're getting at...
interesting, covering mine hasn't seemed to cause my lights
to come on - but then, covering the switch sensor hasn't
seemed to have any effect either, (although I haven't had
both covered at the same time).

I'll be running out to the car in a bit to check - lending further
support to my coworker's suspicion that I'm crazy.
Ha - and they all have pictures of their families at their desks!
:eeps:
 

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bluer1 said:
I'll be running out to the car in a bit to check - lending further support to my coworker's suspicion that I'm crazy. Ha - and they all have pictures of their families at their desks! :eeps:
While you're out there, you may as well do a quick detail of your car and check your tire pressures. That's the accepted "normal" behavior around here. :D
 

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fahrer
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1,387 Posts
My not-so-scientific test revealed that covering both didn't
seem to cause the headlights to come on.

A close look at the rain sensor and there's two sensors,
a large rounded rectangular cutout and a small circular
one to its bottom right (from the front of the car).

Guessing the large one is rain and the small one is headlights,
(or at least contributes to the headlights).

No one saw me... they did bust me spot-cleaning a bird bomb
off the roof before driving home a while back though. Glad it's
not just me.
 
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