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View Full Version : E34/E32 LKM mod for HID/LED. Fix Bulb Failure Warning



shogun
11-28-2011, 05:49 PM
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.
http://i55.tinypic.com/212df1j.jpg
The LKM on my car is numbered 61-35-8-350-377.
http://i53.tinypic.com/e04duq.jpg
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.

http://i53.tinypic.com/oi69o7.jpg
Picture from the other side
http://i55.tinypic.com/2zgvhwk.jpg
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.

posted by toyotahachiroku on BF , Location BC Canada , E34

added from my side:

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

Tiger
11-28-2011, 06:34 PM
I don't know what is the problem with other people's design to fool a simple system check. I had mine on the car for 10 years with no problem at all.

The relay system I hand built is very simple in design... it is only working when the headlight is off. The relay simply present a continuity via a resistor when power is off. When power is on, the resistor is bypassed.

Long time ago, I had a problem of HID not firing up properly and triggers the check headlight problem... of couse the HID is not lit for one side when it happens... Today's ballast has no problem firing up the HID bulb.

10 years since I installed the HID... still work perfect.