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

[5mall5nail5]

^^^ Nex ttime you'll want to have less exposed leads showing and hot glue the assembly down to the PCB.

[demetk]

^^^ Nex ttime you'll want to have less exposed leads showing and hot glue the assembly down to the PCB.

Hot glue, good idea. Not having exposed leads in a box of full of exposed leads?

[5mall5nail5]

Hot glue, good idea. Not having exposed leads in a box of full of exposed leads?

The leads exposed by BMW are held in place. If this dudes solder connection decides to break one day due to vibration who knows what it'll short.

[tazidas]

After running around for about 2 years with hid and fault showing I had given up but then I stumbled on this post and it actually works I have a 95 E34 and only have the chip for the low beam not the fog light one so I thought what the hell give it a go and to my relief it has cured the problem.
All I need now is the fix for the number plate light error as im running leds with error fix relays but they don't work. May go back to standard bulbs unless anyone has a fix for this aswell.

[tazidas]

Used the diagram again and connected 13 14 and 15 to 8 and have cured all lighting issues. Didn't connect 4 as I tried this and it kept throwing up brake circuit error

[attack eagle]

and while you guys are in there, fix the stupid (us version lkm) Fog relay to ground directly to lkm ground instead of thru the high beam filament. jsut have to cut a trace and add a wire.
then you get fogs with highs, and keep fogs working when you have no high beam bulb installed at all

[95///M3]

Mine looks different... Any schematics available for this version ??

[bradbusa]

so if you do this on any number of the circuits attached to those chips, and you get a bulb failure.. will it still give the "bulb out" warning message?

[Binjammin]

Mine looks different... Any schematics available for this version ??

No, but it's fairly easy to figure out. There's going to be at least a couple multiplexer chips. You can cross the part # on the chip to the datasheet at digikey or maybe mouser. You can find the headlight pin you need on the LKM and follow the trace to the appropriate pin on the muxer chip. Ground the appropriate pin and you're good to go. Write it up and add it to this thread.

[Sparke34]

so if you do this on any number of the circuits attached to those chips, and you get a bulb failure.. will it still give the "bulb out" warning message?

No, this will short the circuit to the computer.

[95///M3]

To follow up. I found a newer LKM and used a jumper wire from pin 1 to pin 8 on chip A as indicated and am still getting a F FOG ERROR. Checke fro continuity and it is a solid connection...

Any thoughts?

Jim H.

[shogun]

was this problem solved meanwhile?

[killdamob]

I want to do the mod so I can have highs and fogs, but I'm not exactly sure what you're saying to do. If it matters I also have HID lows and fogs and have modded the lkm so I don't have anything on my dash.

[cddallara]

Huh. I went with 35watt ddm hids and don't get error messages all the time. In fact, less than when I had the stock setup. Certainly not enough to bug me.
Euro lkm. Maybe one of these days I'll pull it out and re solder the connections, but I don't see the need to short anything out.

[eightynine535]

Mods move this to DIY

[killdamob]

and while you guys are in there, fix the stupid (us version lkm) Fog relay to ground directly to lkm ground instead of thru the high beam filament. jsut have to cut a trace and add a wire.
then you get fogs with highs, and keep fogs working when you have no high beam bulb installed at all

I want to do the mod so I can have highs and fogs, but I'm not exactly sure what you're saying to do. If it matters I also have HID lows and fogs and have modded the lkm so I don't have anything on my dash.

[Onizukachan]

On a US LKM, the ground for the fog relay doesn't actually go to ground.
it actually goes to the high beam relay OUTPUT, and uses the high beam filament as a path to ground.

When you turn on the high beams, there is no ground for the fog relay anymore, and the relay opens, turning off the fogs.
Ie, no fogs with high beams on... Or with them unplugged.
THEREFORE, if you sever the trace between them on the LKM and instead actually ground the fog relay to the lkm ground pin, like the EU LKM, the fogs will operate independent of high beam status and stay on.

Make sense now?

[ZenitramNaes]

Now mine is a little different. Am I wrong assuming the following?
photo (5)ed.jpg

[sse34]

Now mine is a little different. Am I wrong assuming the following?
<img src="http://forums.bimmerforums.com/forum/attachment.php?attachmentid=477768"/>

Buy this http://www.theretrofitsource.com/pro...roducts_id=238

No more error afterwards

[ZenitramNaes]

I had bought something similar from DMM tuning and then realized if I could avoid resistors I would.

[sse34]

I had bought something similar from DMM tuning and then realized if I could avoid resistors I would.

These don't catch on fire like ddm's

But to each his own

[js22]

Thank you SO MUCH for this thread ! No longer am I reminded every single day that my (dead, cracked, held-on-by-duct-tape) fog lights fell offa my car on a bumpy dirt road several years ago.

One hair-splitting technical point, though. The chips labeled A and B merely monitor several (8) digital inputs and send them on in serial form. Q : Where do these inputs come from ? A : From the output of another chip ! In particular, from the AD2201-2 chips also on the LKM circuit board. These are the chips that do the analog job of sensing the presence/absence of a bulb filament.

So if you simply ground one of the inputs (say chip A, pin 1 for front fog lights) you are also grounding an output of the partner AD2201-2 chip. The result is likely to be gonna be a hot, possibly destroyed output transistor. Since the purpose of this mod is to ignore the output, probably nobody cares. But in the off chance the failure mode of the AD2201-2 is less pleasant, or (even less likely) that some day somebody wants to undo the mod, it is probably a good idea to be more careful.

What I did was to verify that chip A, pin 1 was indeed the signal I wanted to ignore. Then I cut/scraped away 1mm or so of the PCB trace leading into pin 1. (Verify that it comes from an output of an AD2201-2 chip !). Then I grounded the pin 1 with a short jumper wire to pin 8, as in the original method.

Again, this hardly matters in any practical way. But one of the joys of having a perfect E34 is the ability to switch on your fog lights at any time. In place of that joy, I have the (even greater ?) joy of knowing that a teeny,tiny unwanted transistor could in theory be used again !

[EEDegreeToDrive]

Thank you SO MUCH for this thread ! No longer am I reminded every single day that my (dead, cracked, held-on-by-duct-tape) fog lights fell offa my car on a bumpy dirt road several years ago.

One hair-splitting technical point, though. The chips labeled A and B merely monitor several (8) digital inputs and send them on in serial form. Q : Where do these inputs come from ? A : From the output of another chip ! In particular, from the AD2201-2 chips also on the LKM circuit board. These are the chips that do the analog job of sensing the presence/absence of a bulb filament.

So if you simply ground one of the inputs (say chip A, pin 1 for front fog lights) you are also grounding an output of the partner AD2201-2 chip. The result is likely to be gonna be a hot, possibly destroyed output transistor. Since the purpose of this mod is to ignore the output, probably nobody cares. But in the off chance the failure mode of the AD2201-2 is less pleasant, or (even less likely) that some day somebody wants to undo the mod, it is probably a good idea to be more careful.

What I did was to verify that chip A, pin 1 was indeed the signal I wanted to ignore. Then I cut/scraped away 1mm or so of the PCB trace leading into pin 1. (Verify that it comes from an output of an AD2201-2 chip !). Then I grounded the pin 1 with a short jumper wire to pin 8, as in the original method.

Again, this hardly matters in any practical way. But one of the joys of having a perfect E34 is the ability to switch on your fog lights at any time. In place of that joy, I have the (even greater ?) joy of knowing that a teeny,tiny unwanted transistor could in theory be used again !

In this thread for a Low Beam fail cancel I shorted the output pin of the AD22201 chip responsible for the hot-monitoring half of the circuit. It has an internal pull up resistor, so shorting the pin to ground has no ill effects.
Also in that thread, I attempted to identify several of the other bulb monitoring circuits so folks could do what they wanted with respect to fog lights, parking lights, license plate bulbs, etc.
Over a year after I provided the guidance to a forum member to do a Low Beam fail cancel, I finally got around to performing the mod myself. (I decided to put a 'spare' HID kit in my E34.)

[sse34]

Don't know why people dont just buy a set of error eliminators from theretrofitsource

[Binjammin]

Don't know why people dont just buy a set of error eliminators from theretrofitsource

Because it's a twenty cent fix to hack the LKM versus... whatever the error eliminators cost? At the same time, you don't have the load with the error eliminators versus pulling down a pin on a muxer?