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  #1  
Old 09-06-2003, 10:13 AM
bluer1 bluer1 is offline
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Mein Auto: doesn't have rear fogs!
Rear Fog Light Research (post-facelift E46)

Rear Fog Light Research (post-facelift E46)

After a recent drive home through a torrential downpour, and being tailgated most of the way on the freeway by an A4, I decided to pick up where Kaz left off regarding the rear foglight question. As you'll recall, Kaz figured out everything we'd need to know to add the rear foglight to a pre-facelift E46. The post-facelift E46 received a completely different rear light cluster, which effectively changes some of the information. Here's what I've found after couple of evenings of digging through the ETK and disassembling my car this momrning.

I'll start by addressing the question "why?" first - it's simple. My Volvo had rear foglights and aside from using them in inclement weather, I took great pleasure in turning them on briefly to feign a "brake check" when being tailgaited on the freeway. Granted, we don't get much fog here but we do get the occassional thunderstorm that reduces visibility to similar levels.

Here's what I've found so far:

It appears that the LKM (LCM - Licht Kontrol Module/Light Control Module) is the same base unit in all E46s and differs based on Xenons and Auto Lights (auto on/off of headlights). The unit on Kaz's pre-facelift touring is the same unit on my post-facelift (May '02 build) sedan. The usage info in the ETK shows both ECE and USA market cars as being equipped with the same part(s).

From Kaz's DIY, pin 49 is unused on pre-facelift USA cars and runs the rear foglight on ECE cars. On post-facelift cars, the trunk bulb holder (p/n 63 21 6 907 937) comes with two bulbs (one running lamp, one reverse lamp). The running lamp (in the position of the rear foglight on pre-facelift cars) is yellow w/ black stripe and wired to pin 52 at the LCM.

Pin 49 at the LCM is grey w/ purple stripe and traces to the rear corner bulb holder (63 21 6 907 935) pin 8, which is the inside lower running lamp.

I can't find mention (in the ETK) of the rear foglight bulb being a dual filament bulb, and this position in either holder has a 12v21w bulb from the factory (USA market cars).

Since pin 49 traces to this bulb position, and the LCM is the same on USA and ECE market cars, I'm assuming this means that the post-facelift E46 comes from the factory with the wiring in place.

Unfortunately, my ETK is early 2002 and doesn't show the post-facelift USA parts, (although it does show post-facelift ECE parts). Disassembling my car and examining part numbers shows that my USA market E46 has the same parts the ETK lists for ECE market cars, and the ETK doesn't make a distinction regarding the rear foglight for post-facelift ECE cars.

What does it all mean? Given that all E46s use the same LCMs and position 49 is wired to the corner cluster on post-facelift cars, it appears that:
- post-facelift E46s had their rear foglight moved to the inner lower position on the corner cluster.
- post-facelift E46s have wiring from the factory to support the addition of a rear foglight.

I'd like to ask one of the European listers (with a post-facelift car and rear foglights) to confirm, (this is as simple as following the procedure to change a tailight bulb, requires no tools, and would take ~5 minutes):
- the position of the rear foglight in the cluster
- the p/n of the bulb carrier the foglight is in (assumably the corner bulb holder)
- the number of contacts and wire colors to that bulb (by looking at the connector on the carrier)

If the parts and wiring match up, (which I suspect they will), I'll order a new switch unit for my LCM (see p/n's Kaz's DIY).

I'm fearing that the post-facelift E46 will require vehicle coding to enable the feature, (like the Mini), and that US dealers won't have the proper software. If that's the case, I'll have to see about starting a petition for E46 owners.
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  #2  
Old 09-06-2003, 05:57 PM
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Kaz Kaz is offline
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I'm glad to see that someone has decided to pick this up for the benefit of facelift owners. I know very few owners of facelift sedans, and none so far have approached me about this, so I haven't had the opportunity to work on this.

These findings do look somewhat curious, though. The wire color of pin49 and the assignment of 52 don't match my information (I show 49 being yellow/black, and I show 52 going to the front right auto-level (xenon) /manual level (halogen) unit.

I really hope coding isn't the answer here. I lucked out that there was no coding involved for my project, and was particularly relieved when I heard about the plight of MINI owners.
  #3  
Old 09-06-2003, 07:57 PM
bluer1 bluer1 is offline
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Mein Auto: doesn't have rear fogs!
My plan for now is to disassemble it all again and confirm my notes when I install the Bluetooth stuff later this week. I'll have most of the driver's side trunk lining out for that (and to get a dead bug out of my tailight lens).

Hopefully I'll hear from a European owner early next week (when everyone is back in front of their computers).
  #4  
Old 09-07-2003, 06:02 AM
andy_thomas andy_thomas is offline
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Quote:
Originally Posted by bluer1
Rear Fog Light Research (post-facelift E46)

After a recent drive home through a torrential downpour, and being tailgated most of the way on the freeway by an A4, I decided to pick up where Kaz left off regarding the rear foglight question...

Here's what I've found so far:

It appears that the LKM (LCM - Licht Kontrol Module/Light Control Module) is the same base unit in all E46s and differs based on Xenons and Auto Lights (auto on/off of headlights). The unit on Kaz's pre-facelift touring is the same unit on my post-facelift (May '02 build) sedan. The usage info in the ETK shows both ECE and USA market cars as being equipped with the same part(s).

From Kaz's DIY, pin 49 is unused on pre-facelift USA cars and runs the rear foglight on ECE cars. On post-facelift cars, the trunk bulb holder (p/n 63 21 6 907 937) comes with two bulbs (one running lamp, one reverse lamp). The running lamp (in the position of the rear foglight on pre-facelift cars) is yellow w/ black stripe and wired to pin 52 at the LCM.

Pin 49 at the LCM is grey w/ purple stripe and traces to the rear corner bulb holder (63 21 6 907 935) pin 8, which is the inside lower running lamp.

I can't find mention (in the ETK) of the rear foglight bulb being a dual filament bulb, and this position in either holder has a 12v21w bulb from the factory (USA market cars).

...

I'd like to ask one of the European listers (with a post-facelift car and rear foglights) to confirm, (this is as simple as following the procedure to change a tailight bulb, requires no tools, and would take ~5 minutes):
- the position of the rear foglight in the cluster
- the p/n of the bulb carrier the foglight is in (assumably the corner bulb holder)
- the number of contacts and wire colors to that bulb (by looking at the connector on the carrier)

If the parts and wiring match up, (which I suspect they will), I'll order a new switch unit for my LCM (see p/n's Kaz's DIY).

I'm fearing that the post-facelift E46 will require vehicle coding to enable the feature, (like the Mini), and that US dealers won't have the proper software. If that's the case, I'll have to see about starting a petition for E46 owners.
The arrangement for the E46 rear foglight is completely different to previous 3s. The foglight on my E46 (UK spec 318i) is on the right, driver's side, and it is the same bulb as the inner taillight ("inside lower running lamp"). The bulb has only one filament. The LKM varies the voltage to that bulb to mimic both a taillight and a foglight, depending on whether the rear fog button is pressed. There are no dual-filament bulbs anywhere on the E46.

Sorry, I couldn't see the p/n of the bulb holder. The ETK has it, though:

63 21 6 907 938 Bulb Carrier, Right
.. 937 is the left carrier.

This technology is the same technology that allows other bulbs to take the place of burnt out bulbs. So the outer taillight can double as a brake light if the main brake light fails, or the brake light can double as a taillight (at reduced voltage) if one of the taillights fails. Alternatively, the outer taillight can also double as a foglight if the inner one fails. And so on.

I would imagine all you'd need is a light switch panel with a rear foglight button integrated, and a trip to the dealer to borrow the DIS. I don't know whether they would have the right software, though - I don't understand why BMW doesn't fit rear fogs to its US market cars (or rather, why BMW NA leaves them out - maybe they're in denial about fog ).
  #5  
Old 09-07-2003, 10:50 AM
bluer1 bluer1 is offline
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Thanks Andy - that's all the confirmation I need.

With that, I'm confident that post-facelift E46s all come equipped with the wiring for it from the factory.


I'll order a switch module this week and let everyone know how it goes. I assume it'll take a couple of weeks to get here, since it's probably going to have to come from Europe.

I've got a fairly good relationship with my service manager and shop foreman, (I pass three other dealers on the way to them - a 100 mile round trip - and they know it), so they'd probably help me out as much as they can if recoding is required. Come to think of it, they'd probably even be willing to call BMWNA's tehcnical assistance hotline if they can't figure it out!

It amazes me that BMW doesn't offer this in the US. Drivers here typically have less training, are more emotional, drive bigger vehicles, and follow too closely. I'd obviously be willing to pay extra for it - after all, I paid extra for rear airbags!


I'll keep everyone posted.
  #6  
Old 09-08-2003, 06:03 AM
OBS3SSION OBS3SSION is offline
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bluer1,

If coding is needed, and it looks like starting a petition to BMW NA is the way to go to get these activated... then I'll be the second name on the list after yours.

Rear fogs should be mandatory in the US... just as training all the morons on the road correctly should be mandatory. But regardless, I want my rear fog, and find it a valuable safety feature. We may not have heavy fog that often, but we have rain... and the spray on highways on a rainy day is as just as bad or worse than fog. When I can't see the car in front of me, I know the moron behind me can't see me either. That light will protect my arse.
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  #7  
Old 09-08-2003, 07:53 AM
bluer1 bluer1 is offline
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Mein Auto: doesn't have rear fogs!
The part is on the way from Germany, ETA two weeks.
I'll know something the day it arrives.
  #8  
Old 09-08-2003, 07:17 PM
Parump Parump is offline
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Quote:
Originally Posted by OBS3SSION
bluer1,

If coding is needed, and it looks like starting a petition to BMW NA is the way to go to get these activated... then I'll be the second name on the list after yours.

Rear fogs should be mandatory in the US... just as training all the morons on the road correctly should be mandatory. But regardless, I want my rear fog, and find it a valuable safety feature. We may not have heavy fog that often, but we have rain... and the spray on highways on a rainy day is as just as bad or worse than fog. When I can't see the car in front of me, I know the moron behind me can't see me either. That light will protect my arse.
  #9  
Old 09-08-2003, 09:08 PM
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operknockity operknockity is offline
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Quote:
Originally Posted by bluer1
The part is on the way from Germany, ETA two weeks.
I'll know something the day it arrives.
Cool
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  #10  
Old 09-10-2003, 03:14 AM
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Mein Auto: E46 E83 E30- all M sport!
keep us posted.... i had to run all the wires to the trunk for my rear fog, now i just have to order the switch for the LCM and hook up the wires to the LCM.....
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  #11  
Old 09-10-2003, 06:20 AM
sdwolff sdwolff is offline
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[QUOTE=OBS3SSION]bluer1,

If coding is needed, and it looks like starting a petition to BMW NA is the way to go to get these activated... then I'll be the second name on the list after yours.[QUOTE]

A petition worked for MINI. BMW/MINI said no to rear fogs, until they owners ganged up. Now it's retrofitable and will be on future cars.
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  #12  
Old 09-17-2003, 08:31 AM
bluer1 bluer1 is offline
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Mein Auto: doesn't have rear fogs!
Update - The part is in the States and my dealer shipped it out on 9/12.
I should know something this weekend.
  #13  
Old 09-18-2003, 10:30 AM
bluer1 bluer1 is offline
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Hmmm... the Big Brown Truck just dropped this off...


grainy photo from T610.
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  #14  
Old 09-18-2003, 10:53 AM
OBS3SSION OBS3SSION is offline
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Droooool... please, please work!
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  #15  
Old 09-18-2003, 11:31 AM
bluer1 bluer1 is offline
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Quote:
Originally Posted by OBS3SSION
Droooool... please, please work!
All I know so far is that it isn't going to be plug & play.


I brought my Fluke, but had to give up before I ended up with wires everywhere and my boss wondering where I'd gone.
  #16  
Old 09-19-2003, 01:11 AM
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Quote:
Originally Posted by bluer1
All I know so far is that it isn't going to be plug & play.


I brought my Fluke, but had to give up before I ended up with wires everywhere and my boss wondering where I'd gone.

find out anything yet???? don't leave us hangin'.....
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  #17  
Old 09-19-2003, 06:40 AM
bluer1 bluer1 is offline
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Quote:
Originally Posted by Dirtboy
find out anything yet???? don't leave us hangin'.....
Well... I was going to wait until I had a little more, but since you asked...


Here's where I am with it:

Having already tried BMWNA's main number and "Priority Mail" through the Owner's Circle, I started to try to contact people yesterday:
- the folks responsible for the Mini petition
- the journalist that broke the Mini story
- an individual at BMWNA

As previously posted, I mounted the new switch at lunch - no joy.

I took apart the LCM and removed the back covers from the switch modules and started poking around the harness again.

Notice the red circles in the photo of the switch modules, (the top switch is the ECE version, the bottom is the USA version). I found it curious that the ECE switch uses a different set of contacts for the front fogs than the USA switch - there's three sets of contacts on the board, and the USA version uses the center contacts as a soft switch for the front fogs, which operates a relay behind the glovebox. The ECE switch uses a different set of contacts for the front fogs, but still operates my USA car identically to the USA part, (no surprise there).

The boards are identical, only the front fascia and buttons are different.

Knowing from ETK that USA/ECE cars share LCMs, I traced pin 49 in the LCM harness to the pin 8 in the rear corner bezel, the middle lower running lamp, (or the inside lower lamp on the corner cluster), not the trunk running lamp. From what I can tell, it's a direct wire.

I also confirmed yesterday (after spending a lot of time in ETK/TIS) that the rear fogs don't have a relay like the fronts do. The Mini is set up this way as well, and it makes sense as the rear fog isn't going to require near the current that the front fogs do.

After buttoning it all up last night, I went back out and tore into it again wondering if I could artifically create a bulb fault and trigger the LCM to move the rear fog to another location. (I was thinking maybe something wasn't wired, like the pre-facelift cars.) Again, no joy. I did determine that the adaptive lighting works! (The brakelight will move if the bulb goes out!)

I'm going to try and run down some schematics today. Without a breakout box and knowing what I'm looking at, I'm a little leary of probing too much stuff with the meter.

FWIW, I also confirmed that the E46 chassis doesn't require vehicle coding for the front fogs.
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Last edited by bluer1; 09-19-2003 at 06:48 AM.
  #18  
Old 09-19-2003, 07:10 AM
bluer1 bluer1 is offline
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Mein Auto: doesn't have rear fogs!
Update - I just got off the phone with my contact at BMWNA. He's going to follow up everything with their technical engineers and let me know exactly what I need to do!
  #19  
Old 09-19-2003, 07:21 AM
OBS3SSION OBS3SSION is offline
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You will be a hero to many if you can make this happen!

This morning, driving to work in the heavy rain of Hurricane Isabel, I was thinking to myself how badly I wanted to turn on a rear fog because I was having difficulty seeing the bloke in front of me.
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  #20  
Old 09-19-2003, 08:23 AM
tgravo2 tgravo2 is offline
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I would definately love to see the results
  #21  
Old 09-19-2003, 08:26 AM
m3again m3again is offline
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I am eagerly awaiting this, too! Good luck and thanks again for taking the lead on this.
  #22  
Old 09-19-2003, 09:33 AM
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Kaz Kaz is offline
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oh boy... If this was what I was facing, I probably woulda given up by now! Good luck!
  #23  
Old 09-19-2003, 09:55 AM
bluer1 bluer1 is offline
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Quote:
Originally Posted by Kaz
oh boy... If this was what I was facing, I probably woulda given up by now! Good luck!
Oh... I should clarify. I disassembled the LCM just out of morbid curiosity, (and to see if it would be easy to trace through it).

I suspect there's going to be some software issue, like the Mini.
  #24  
Old 09-19-2003, 12:23 PM
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Terry Kennedy Terry Kennedy is offline
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Quote:
Originally Posted by bluer1
Oh... I should clarify. I disassembled the LCM just out of morbid curiosity, (and to see if it would be easy to trace through it).

I suspect there's going to be some software issue, like the Mini.
Same here. Can you post what all the text from the sticker on your LCM says? I'll compare it with mine and let you know any differences.

If you install the Euro front switch assembly and make sure you have your front headlights and fog lights on, then push the rear fog button, does the rear fog light indicator in the instrument cluster turn on?

If that works, they may have just mapped the rear fog power line to a different pin on the LCM for some reason. What pins are vacant in the vehicle harness going to the LCM?
  #25  
Old 09-19-2003, 01:12 PM
bluer1 bluer1 is offline
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Mein Auto: doesn't have rear fogs!
Quote:
Originally Posted by Terry Kennedy
Same here. Can you post what all the text from the sticker on your LCM says? I'll compare it with mine and let you know any differences.

If you install the Euro front switch assembly and make sure you have your front headlights and fog lights on, then push the rear fog button, does the rear fog light indicator in the instrument cluster turn on?

If that works, they may have just mapped the rear fog power line to a different pin on the LCM for some reason. What pins are vacant in the vehicle harness going to the LCM?
Absolutely! (from my 05/02 USA 330i):

BMW 6 919 847

037239075 0017385 21
US SA dyn.LH m FLC 21641
Lear HW:16 SW:3.01

Yes, the rear foglight dash indicator lights up. The wiring has most certainly changed, along with the light bezels.

I'm stopping until I hear back from BMWNA - or perhaps, until this weekend, depending on my schedule. My next step would be to tie into all the vacant LCM pins and look for a current change when turning on the rear fogs and/or tracking down a schematic.

I suspect the wiring is in place since all lamp positions are used and BMW uses current changes rather than dual filament bulbs, (so there's only ever one wire per bulb, plus ground distribution at the bezel).

See attached image files for the spacing and harness colors.
Sorry - I couldn't get vlinto working and the embedded html kept screwing up.

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Last edited by bluer1; 09-19-2003 at 01:22 PM.
 

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