E34 LKM mod for HID/LED. Fix Bulb Failure Warning

[toyotahachiroku]

I recently bought some cheapo hid and the Low Beam Failure warning light came up every time I turned the lights on. I've tried using a resistor. The same kind sold over ebay. Did not always eliminate the Low Beam warning. Considered a failure. Thanks Shogun for pointing out a Japanese site with a lot of BMW DIY. I don't know much Japanese so I half guess and half google translated it. Although the Japanese and Euro LKM are slightly different. The same theory applies. I don't guarantee everything is 100% correct. Use at your own risk. Here are my results.

The are two 16 pin chips on the board. Basically Pin 8 is ground. Grounding any of the other pins to 8 will eliminate the warning. Perfect if you want to run HID or LED all around and don't want to use the ridiculously hot heat sink resistors just to eliminate the warning. This mod won't fix hyper flashing problems though.



The LKM on my car is numbered 61-35-8-350-377.



This is an after picture. I installed HID low beam and HID fog lights so I soldered a connection between pin 1 and 8 on chip A for Fog Light and pin 1 and 8 on Chip B for Low Beam.



Picture from the other side



Zoomed out.

After installing the LKM back in the car, I tested to see if the warnings would come back on. I ran halogen bulbs on one side and no bulbs on the other. No warnings. Then I ran just HID on one side of the car and no bulbs on the other side. No warning. Disconnected all the low beam and fog bulbs. No warning. All other lights work properly.

ps. good time to check for loose components and re-solder if necessary.

[jgdynamics]

with hid fogs i never got an error message and that was with my 91 525i, i never tried hid fogs on my 95 540i. do you know if they are the same? i have led license plate lights, so i might do this for the license plate and the low beams. good info. thanks!

[jgdynamics]

with hid fogs i never got an error message and that was with my 91 525i, i never tried hid fogs on my 95 540i. do you know if they are the same? i have led license plate lights, so i might do this for the license plate and the low beams. good info. thanks!

[5senses]

Great info and pics!..

Wes

[uk525td]

good stuff, was planning something similar when i eventually go HID!!!! glad somone else did the ground work

[Bwaterman]

Very nice work!

I hate using load resistors because the main benefit of LED's are low power use which goes out the window when you use the resistors.

How do you work out which pin is for which error? I have a euro car so mine could be different.

[AHenry014]

this is great. i need to be rid of my parking light error (smileys). the last time i did this however, for my HID fogs....i used a resistor in line for simulation. just followed another thread.

[AHenry014]

this is great. i need to be rid of my parking light error (smileys). the last time i did this however, for my HID fogs....i used a resistor in line for simulation. just followed another thread.

[Steve547i]

So happy you did this.

[dme88]

You could actually just replace the shut resistor with a bigger one and the light warning will work for HID lights too. Those >1.0W resistors are not cheap tho.

[RVAE34]

Awesome!!! Thanks for the great writeup!

[5mall5nail5]

Another bump for excitement. This should be thrown in the DIY etc section. I am going to do this tomorrow. I was just looking for DDM-style error cancel thingers, and wanted to figure this out so long ago, but never did. This is great.

[84318i]

Awesome, I'll do this as well.

[Bwaterman]

does anyone know how to identify which pins monitor which lights?

[DUDMD]

does anyone know how to identify which pins monitor which lights?

I don't see why it could be different on the chip contacts. I guess you could trace it from the wiring harness plug with a multimeter to verify.
http://www.bimmerboard.com/forums/posts/425247


Those of you that don't want to solder the LKM can do similar to what is done up above, just with the wiring inputs to the LKM/CCM. I would highly reccomend against it, simply because another used LKM can be had for cheap if you burn it to hell, not the same can be said about wiring after you hack it up.

[camaroguy]

Its interesting that the warning came on when you turned the lights ON. There should still be some resistence across the ballast which prevents that from happening. There is in my cheap kit anyway.

The problem I had was the failure warning when I shut the lights off. There is infinite resisntance then because the balast isnt doing anything. I just soldered the resistor inside the lkm so its all clean looking. Just enough for it to think a bulb was there but not turned on.

Just to clerify, you have completely eliminated the warning by doing this? It will not tell you if the bulbs actually burn out now?

I was not sure if it would tell me or not being as there is a balast between the lkm and the bulb. I unplugged one bulb and it still told me that the bulb was bad.

[5mall5nail5]

Its interesting that the warning came on when you turned the lights ON. There should still be some resistence across the ballast which prevents that from happening. There is in my cheap kit anyway.

The problem I had was the failure warning when I shut the lights off. There is infinite resisntance then because the balast isnt doing anything. I just soldered the resistor inside the lkm so its all clean looking. Just enough for it to think a bulb was there but not turned on.

Just to clerify, you have completely eliminated the warning by doing this? It will not tell you if the bulbs actually burn out now?

I was not sure if it would tell me or not being as there is a balast between the lkm and the bulb. I unplugged one bulb and it still told me that the bulb was bad.

If you solder a resistor in the LKM like pictured above all you are doing is shorting to ground with a slightly higher ground reference. I'd recommend removing the resistor and directly shorting the pin to ground so that you don't involve any ground shift or floating ground issues.

[camaroguy]

Thanks John, I will clerify. I did not solder the resistor in the spot where he soldered those wires. I soldered it across the output pins to the headlamps. Its basically the same as having the halogen bulb plugged into the harness as well as the HID's. Yes I am burning an extra watt while my lights are on, but its not a big deal since my hid's are only 35w anyway, and the original halogens are 55w.

I was just trying to clerify that what he was doing is actually bypassing the signal all together. I still get the bulb out message if one of my hid's dies...It will only happen when they are on, unlike the factory halogen setup which happens when they are off as well.

[5mall5nail5]

Yeah I don't prefer that method because you have a clunky resistor floating around under the hood which is 1) hard to hide and 2) can fail over time due to sinking heat. I think the LKM solution is best. You can really notice when one headlight goes out so I don't think a message is really necessary.

[camaroguy]

Its pretty easy to hide when its inside the LKM I also don't agree that its "easy" to know a headlight is out when you drive around a lot of lighted streets...especially with HID's.

[5mall5nail5]

Its pretty easy to hide when its inside the LKM I also don't agree that its "easy" to know a headlight is out when you drive around a lot of lighted streets...especially with HID's.

Usually you need to use large-ish resistors. You fit a 1W resistor in the LKM?

[camaroguy]

They may not be 1 watt resistors, I don't exactly remember. They are largish, I know they have been working flawlessly for 4 years and about 25k miles though

[shogun]

LKM-L and LKM-B pin -out

1 High Beam stalk at steering wheel
2 terminal 30 (continious power)
3 switch low beam/dip light
4 data to CCM = check control module
5 data to CCM = check control module
6 F1 terminal R, IC supply
7 from k7 P2 - tail light right

8 tail light right
9 tail light left
10 parking light right
11 parking light left
12 from brake light switch

13 brake light left
14 switch licence plate light on
15 3rd brake light
16 fog light front left
17 F7 15A, terminal 30
18 fog light switch
19 rear fog light switch

20 high beam via fuse F13, F14
21 low beam left F10
22 low beam right F11
23 check via CCM + CC + OBC (check control module-check control-on board computer)
24 ground
25 data to CCM

26 from K7P6 tail light left
27 from K7P9 parking light right
28 from K7P5 parking light left
29 brake light right

30 licence plate right
31 licence plate left
32 fog light right, front
33 fog light right, rear
34 fog light left, rear
35 F8 15A for rear fog light

Note: this is the ECE/EU version, some pins might be missing in other versions. But the set - up will be the same. So for the US LKM probably the pins for rear fog light might not be there respect. not connected internally.
Depending on year of production and the makers of the LKM the internal parts look different, but the pins are always for the same function.

The pins in one row are 1 - 19
and the other row
20 - 35

[toyotahachiroku]

been using the same lkm i did the mod to since august. no error codes related to lights ever. it won't show errors with burnt bulbs. no error messages for having no bulbs at all either. running 6 cheapo hid up front with led city lights. i've actually soldered on more connections so no bulb shows errors ever.

[demetk]

If you solder a resistor in the LKM like pictured above all you are doing is shorting to ground with a slightly higher ground reference. I'd recommend removing the resistor and directly shorting the pin to ground so that you don't involve any ground shift or floating ground issues.

I did this for my lows and fogs. Courtesy of Shogun I believe.