Xenon to Bi-Xenon DIY Retrofit Instructions

First off, I cannot take any credit for this whatsoever. Member Scott (ScottZHP from bimmerfest) came up with this. I just organized it all for my installer, so I figured I'd share it with everyone.


Quick background:

All pre-2002 e46s came with standalone Xenon headlights (or straight halogen headlights). On the Xenon headlights, halogen lights are still used for the high beams, as well as flash-to-pass. (NOTE: All Projector 46s are single Xenon headlights, using a halogen high beam)

In 2002, the e46 had an option for bi-xenon headlights. The bi-xenon was a great improvement over the regular xenon, because instead of using a halogen light for a high beam, it opened the shutter “eye” of the xenon projector, and used Xenon light for a high beam as well. The difference in light output is tremendous. The halogen bulb remains in the car only for flash-to-pass. This is done to protect the Xenon ballast / igniter, from potential damage with quick a ON-OFF for flashing the lights (Xenon lights also take longer to turn on, making halogen light’s instant-on a better choice for flashing).

Anyhow, anyone with a 2002+ e46 could swap halogen lights with bi-xenon’s and get functioning single Xenon’s, by simply plugging in bi-xenon’s where the halogens had been, and then having the car’s LCM flashed at the dealer. In order to get the bi-xenon functionality working, you need to do some extra wiring.

Scott’s original DIY is here:
http://www.bimmerfest.com/forums/showthread.php?t=46813

I have cleaned those instructions up into an easy-to-print PDF file, and located it here:
http://www.bigpatsfans.com/bixenon.pdf

For most people, the above instructions work perfectly. However, there are cases in which you will need to modify them slightly. Any car built prior to 2002 that wants to add bi-xenon’s, will need to make changes to the wiring in order to get this to work. Unfortunately, the car’s computer components are too old to accept the programming for retrofitting bi-xenon’s, so the changes essentially need to be made with wiring instead. (My car is a 2001, which I facelifted to the 02-05 body style, so I am using bi-xenon headlights. Up until yesterday, my bi-xenon’s were acting as single xenon’s.


Here are the changes that need to be made in order to get bi-xenon working in a car that was never meant ot have it.... Courtesy of Scott:

This circuit is just a solid state version of what the LCM bi-xenon programming would do. You are just inserting the relay into the high beam feed and using the low beam presence to tell the relay to switch on one or the other. Simple as pie.

You should be able to accomplish what you want by using a SPDT (single pole double throw) Bosch-style relay wired into the high beam circuit using the low beam as a coil trigger. A SPDT relay has 5 terminals instead of the usual 4.

Your dilemma is that you need to use the low beam voltage (or absence thereof) to determine which high beam source you want to power: Halogen or bi-xenon, but not both. If the low beam xenon’s are ON, you want to power the bi-xenon plug to open the shutter and not the halogen high. If the low beams are off, you want to power the halogen high beam plug and not the shutter.

Relay wiring is as follows:

Pin 85 - tap into low beam +12V (don't cut if off, just tap into it)
Pin 86 - ground
Pin 30 - from LCM high beam to high beam headlight (splice, cut if off)
Pin 87 - to bi-xenon shutter
Pin 87A - to halogen high beam plug

What happens is that pin 87A is normally closed and will be powered (by pin 30) when the relay coil is not energized. When the coil is energized (by sensing low beam xenon), pin 87 gets power and shuts off 87A.

You're using the low beam presence on pin 85 to trigger the coil and select which plug you want to feed.

The only unknown is what happens in pathway mode (ignition is off, xenon’s come on for 30 secs to illuminate, then shut off). I have not probed with a meter to see what gets power in this mode. Maybe tonight I'll poke around.


**

I’ll post some more details from my installer later on.

Glad to hear this worked!

Dont forget to fuse the relay (the lead to Pin30) and you might want to add a diode across the coil.

Originally Posted by Scott

Glad to hear this worked!

Thanks again Scott! This could be invaluabel to people with pre-02 M3s and coupes, who can easily swap newer headlights in...

People with prefacelift sedans could always swap the projectors from the newer headlights into their old housings.

For those of us that live in areas where high beams are used a lot, this is a huge plus!

One note here I forgot to mention...

The way the bi-xenon setup functions is a slightly different from factory. The factory bi-xenon system on an e46 flashes the halogen inner lights for flash to pass (pull back on blinker stalk) regardless of the current state of the low beams.

This setup is slightly different:

Flash-to-pass uses the halogen when the lights are off...

Flash-to-pass uses the shutter when the headlights are on.

I think that is totally fine. I think the main thing to avoid was having the Xenon's fire up (ballast and igniter) when the headlights were off. That quick ON-OFF would probably kill the ballast / igniter eventually... Having the shutter open for flashing when the headlights are already ON is OK IMO.

Originally Posted by sna77

One note here I forgot to mention...

The way the bi-xenon setup functions is a slightly different from factory. The factory bi-xenon system on an e46 flashes the halogen inner lights for flash to pass (pull back on blinker stalk) regardless of the current state of the low beams.

This setup is slightly different:

Flash-to-pass uses the halogen when the lights are off...

Flash-to-pass uses the shutter when the headlights are on.

I think that is totally fine. I think the main thing to avoid was having the Xenon's fire up (ballast and igniter) when the headlights were off. That quick ON-OFF would probably kill the ballast / igniter eventually... Having the shutter open for flashing when the headlights are already ON is OK IMO.

sna77,

hey i haven't wired my car yet for bi-xenon operation but i bought all the bmw parts i need per Scott's diy. already got the connectors and relay and i made all the harnesses. is this relay your referring to the same as the one i have with the 2 87 pins ?

just curious. not sure if i want to use your method instead....i'm swapping out my lcm and want to make sure my car will accept the bi-xenons and leds without errors after i recode.

Originally Posted by sakman74

sna77,

hey i haven't wired my car yet for bi-xenon operation but i bought all the bmw parts i need per Scott's diy. already got the connectors and relay and i made all the harnesses. is this relay your referring to the same as the one i have with the 2 87 pins ?

just curious. not sure if i want to use your method instead....i'm swapping out my lcm and want to make sure my car will accept the bi-xenons and leds without errors after i recode.

If you have an 02, I believe you can use Scott's original methos, as bi-xenons were available in 02

this is the whole thing that's been shot around the forums for the past week or so....

not all '02 models had bi-xenon as an option, until build date 10/2001 and later. because if they did, then i would have the harnesses for bi-xenon shutter and auto-leveling, my car's build date was 9/2001.

and so, instead of referring to models that offered bi-xenon option as 02 models, they should be referred to as 02.5 models, imo....

this is how bmw, mercedes, vw and audi operate. somewhere thru the production life of a body, they will change things right at about a mid-year, and so people tend to refer to their models as 2000, 2000.5, etc....
i guess they do it to keep people entertained as to what options are available for their models. if they didn't change things up i guess they'd lag behind the other makes when it comes to features for car's in similar classes...

Originally Posted by sakman74

this is the whole thing that's been shot around the forums for the past week or so....

not all '02 models had bi-xenon as an option, until build date 10/2001 and later. because if they did, then i would have the harnesses for bi-xenon shutter and auto-leveling, my car's build date was 9/2001.

and so, instead of referring to models that offered bi-xenon option as 02 models, they should be referred to as 02.5 models, imo....

this is how bmw, mercedes, vw and audi operate. somewhere thru the production life of a body, they will change things right at about a mid-year, and so people tend to refer to their models as 2000, 2000.5, etc....
i guess they do it to keep people entertained as to what options are available for their models. if they didn't change things up i guess they'd lag behind the other makes when it comes to features for car's in similar classes...

Looks like you'll need to wire it up like I did then too. =(

wait...you mean that the 'oem' approach to this is not going to work ? what i mean by 'oem' approach is getting the right LCM, running the wires from pin 2 (LCM) to the relay to the bi-xenon connectors on the lights. then a recode of the car's computer to recognize bi-xenons (led's if present)....

i thought this method worked for everyone that's done it to their car.

Originally Posted by sakman74

wait...you mean that the 'oem' approach to this is not going to work ? what i mean by 'oem' approach is getting the right LCM, running the wires from pin 2 (LCM) to the relay to the bi-xenon connectors on the lights. then a recode of the car's computer to recognize bi-xenons (led's if present)....

i thought this method worked for everyone that's done it to their car.

Correct. Even with a new LCM, the car's K-bus system is too old to recognize the bi-xenon programming. You'll still need to do the wiring Scott described for me to do this.

These are your options:

1. Leave current LCM in. Have dealer flash for Xenons. bi-xenon headlights act as regular headlights. Do my wiring to enable bi-xenon functionality.

2. Replace LCM (for LED tail lights). Flash for Xenons. At this point, bi-xenons will work as regular Xenons, and tail lights will work fine. If you want bi-xenon functionality, you'll need to do the manual wiring Scott described.


Also, you have one minor presumuntion wrong from above. Say you bought an 04 with halogens, then went out and bought some bi-xenon headlights. You'd go to the dealer, have the LCM flashed, and your bi-xenons would work like regular Xenons. The bi-xenon wiring is not installed in any car that did not come from the factory with them You'd either need to do Scott's method #1 or #2 for wiring.

okay....

let me see what you'd say to this then:

i have a car that was build date 9/2001, before the 10/2001 update to bi-xenon/led.

what i plan to do is get an lcm that supports xenon and led, install it, install my bi-xenon headlights and led's. then take it to the dealer for a recode. then come home and install the wiring for bi-xenon operation per Scott's original DIY on bimmerfest (pin 2 LCM, then relay with 2 87's, one for each shutter control on headlights).

will this work ? in other words, will this enable the bi-xenon operation and eliminate strobing (both led and xenons) ?

Originally Posted by sakman74

okay....

let me see what you'd say to this then:

i have a car that was build date 9/2001, before the 10/2001 update to bi-xenon/led.

what i plan to do is get an lcm that supports xenon and led, install it, install my bi-xenon headlights and led's. then take it to the dealer for a recode. then come home and install the wiring for bi-xenon operation per Scott's original DIY on bimmerfest (pin 2 LCM, then relay with 2 87's, one for each shutter control on headlights).

will this work ? in other words, will this enable the bi-xenon operation and eliminate strobing (both led and xenons) ?

You have it perfectly correct until the last sentence: then come home and install the wiring for bi-xenon operation per Scott's original DIY on bimmerfest (pin 2 LCM, then relay with 2 87's, one for each shutter control on headlights).

I believe your car is too old for this to work. You need to do the wiring that I did, per Scott's modified DIY.

FWIW, they're just minor differences in the wiring... You still need the same parts. I'd print out both directions when working on it that day. Haha

okay....

i just wanna do the right thing, so instead of getting lost and confused in this and spending more money on things i don't necessarily need....maybe the best approach for me would be to do the install for the headlights/LEDs, then watch and see what happens. then if i get strobing in the tails i have an option....get resistor packs, or get the new LCM.

but if i get the new LCM and my tails stop strobing, then wouldn't logic follow that i can use this new LCM to wire my bi-xenon curcuit ? i mean, wouldn't the new LCM allow control of the bi-xenon feature thru pin 2 since it is recognizing my new tails ?

now i'm a bit confused, because if the bus of the vehicle is re-programmable, then i would assume that it can accept the instructions in the recode and when combined with the correct LCM, should allow functionality for bi-xenon/auto-level features, no ?

i am waiting for ko to get back to me regarding the LCM i need to get, when they do i will run this by them because they would know about it for sure.....

but if i did have to use your method instead, how would i do it and keep things neat under the hood. are the wires i would need to tap in the ecu/relay box ? or would i have to tap near the connectors @ the headlights ?

Originally Posted by sakman74

then wouldn't logic follow that i can use this new LCM to wire my bi-xenon curcuit ? i mean, wouldn't the new LCM allow control of the bi-xenon feature thru pin 2 since it is recognizing my new tails ?

You would think... But it doesn't... I have no idea why... but apparently there is something else that needs to be updated besides the LCM for this to work. The LED tails ONLY require updating the LCM. Noone has figured out what the other thigns are that need to be updated yet. DME, ECU? Etc, etc. The LCM is not the only computer in the car.

Originally Posted by sakman74

i am waiting for ko to get back to me regarding the LCM i need to get, when they do i will run this by them because they would know about it for sure.....

Contact Jason at Tischer. I guarantee he beats their price.

Originally Posted by sakman74

but if i did have to use your method instead, how would i do it and keep things neat under the hood. are the wires i would need to tap in the ecu/relay box ? or would i have to tap near the connectors @ the headlights ?

Doing Scott's method 1 or method 2 is identical for keeping it clean. You cant tell any wiring has been done under my hood at all. I believe everything taps at the ECU, but double check with Scott

does Tischer have experience recoding e46's ? maybe they can tell me what i need to do ?

if bi-xenons do not require a new LCM, then i can live with resistor packs for my LEDs, so that i don't go and spend the extra money on an LCM....the recode would take care of xenon strobing anyway, so then a new LCM wouldn't be necessary.

your method of doing this is vuage....what wire is the one from the LCM that i am supposed to cut ? or more importantly, where can i find all the wires that i would need to work with if i wanted to do it your way ?

so like before, i can still use the relay that i bought, but i still don't understand what you mean by 87A. per Scott's diy, the 2 87's on the relay are used, one to each headlight. am i now using 87 # 1 to both headlights, then 87 # 2 for something else ?

sorry if you've explained this before but i am not familiar with which wires are which in the ecu/relay box. if you have a schematic that would be perfect....

even a snapshot of what's going on in your ecu/relay box can tell me which wires i need to work with.

very much appreciate you giving me advice on all this. other people would have given up by now.....

Originally Posted by sakman74

does Tischer have experience recoding e46's ? maybe they can tell me what i need to do ?

if bi-xenons do not require a new LCM, then i can live with resistor packs for my LEDs, so that i don't go and spend the extra money on an LCM....the recode would take care of xenon strobing anyway, so then a new LCM wouldn't be necessary.

Tischer is a parts department. I have no idea about their service department.

Recoding the LCM is easy. Any BMW dealer can do it and knows how to.

If I were you, I'd order an LCM from Tischer, install it and my LED tails, then drive to my local dealer and have them code it.

Originally Posted by sakman74

your method of doing this is vuage....what wire is the one from the LCM that i am supposed to cut ? or more importantly, where can i find all the wires that i would need to work with if i wanted to do it your way ?

so like before, i can still use the relay that i bought, but i still don't understand what you mean by 87A. per Scott's diy, the 2 87's on the relay are used, one to each headlight. am i now using 87 # 1 to both headlights, then 87 # 2 for something else ?

sorry if you've explained this before but i am not familiar with which wires are which in the ecu/relay box. if you have a schematic that would be perfect....

even a snapshot of what's going on in your ecu/relay box can tell me which wires i need to work with.

very much appreciate you giving me advice on all this. other people would have given up by now.....

Don't worry about it for now... Just get the LED tails, new LCM and dealer flashing done. You're spending all your time worrying about the last, and least important step.

Originally Posted by sna77

Don't worry about it for now... Just get the LED tails, new LCM and dealer flashing done. You're spending all your time worrying about the last, and least important step.

ok well, when you say reflash the LCM, do you really just mean reflash the LCM, or reflash the CAR ?

there are other onboard computers. i'd like to knock off the xenon/LED gig in one shot.

i'll then do your proceedure with the bi-xenons (if you could guide me thru it) and of course wind up owing u a couple of cases of beer or somethin....

has anybody tried doing it @ a performace shop ? i found one that has experience doing this stuff and they say it's cake to do.