[BigMofoFrog]

I thought I would detail my M850i conversion to European Amber tail lights and rear fog lights should anyone be interested in this in the future. I want to start by thanking Shawnsheridan for his advice and latest software links for coding and a huge shout out to larrylam646 on the G20 subforum, who spent his own time troubleshooting, showing me the coding ropes and helping me through this. I'll do my best to pass it forward.

Disclaimer: This is provided for info only and is at your own risk should you try this on your own... to be honest, my heart raced a few times during this project at the thought of bricking my beloved car. The wiring and parts replacement is easy, the coding itself if not done correctly can result in an inoperable car. I took Larry's advice and started with a small project to get comfortable with coding, in my case re-code the decoded antidazzle Laser lights.

I ordered the European tail lights (4) and the correct light switch with rear fog light button from Schmiedmann. They were great to deal with and shipping was prompt.

Part numbers below:

63-21-7-445-771 - tail outer left

63-21-7-445-772 - tail outer right

63-21-7-445-778 - tail inner right

63-21-7-445-775 - tail inner left

61-31-9-461-122 - lighting control panel w/rear fog switch


Start by studying the wiring diagrams in NewTis under 'Body' for the rear tail lights.

I started by running two wires from the BDC A258.5B Pins 12 and 20, located in the passenger side footwell to their respective inner tail light connectors. I used pin connectors (61138369696) that are crimped to a short length of wire as if you just buy the separate pins I found it difficult to get the crimps perfect and would not slip easily into the connectors. I soldered the wire to wire connections and shrink tubed to seal them from moisture. Running these wires (I used 20ga as it was closest, but not smaller to the metric equivalent of 0.35) went under the passenger side door, rear seat side panel and trunk. Make sure to secure the wires with tape and/or zip ties as they run close to, and along the passenger side trunk hinge. Have a read in NewTis for the removal and replacement of all the interior panels. A good non marring interior interior trim tool kit is essential.

Important! While you are at the BDC. There are two wire connectors that must be moved on the M850i, and likely common to all 8 series, from connector A258.5B pin 41 to A258.3B pin 50 and A258.5B pin 33 to A258.3B pin 38. This is an obscure USA to ECE difference between other models as if this is not done, your inner amber lights will be unpowered and will result in hyper flash and left and right rear tail light dash warnings ... don't ask how I know this LOL! Simply use the tool to press the release tab on the pin and it slides right out of the connector, and it slides right into its new position. Create a little wire slack by trimming the tape of the 5B bundle back to allow it to span over to the 3B connector without tension.

I replaced the NA (SAE) tail light assemblies with the European (ECE) tail lights. This was a relatively straight forward job, but make sure to use a magnetic pick up tool to grab the nut as you remove the outer tail light nuts (3 per unit) as they are between panels through small access holes. They would be hard to get if dropped.

The replacement light switch just pops out with a trim tool and one connector is connected and replaced.

Once connected I checked function and as expected the amber turn signal come on with the brake lights. Fog lights (both left and right inner tails for the 8 series) lit up confirming function.

For coding, my car had been recently updated to 07.2020. I used EsysX, Esys 3.33.4 and psdzdata 4.24.31. I was fortunate that LarryLam186 had already done this project on the his G20, and the G15 has a lot in common with the the M340i electronically speaking. The car drew no more than 21 amps with lights in the off position and the AC system turned off. Ensure you have a charger with a true power supply mode that will accommodate this. Mine was a CTEK MULTI US 25000.

There is lots of info on coding. But in a nutshell. Edit your "typeschlussel" from the USA code of 'BC43' to the ECE code of 'BC41'. After reading ECU, right click on BDC_BODY3 and click code. This 'VO' Codes your BDC_BODY3 only to European specs (ECE). Not your whole car.
You will then need to FDL code a few individual parameters within the BDC_BODY3 ECU back to NA specs listed below. There are some other options listed in larrylam646's instructions as well on the G20 forum that can be reverted to NA values. Note++ can be downloaded to verify "compare" the NA and ECE values in the CAFD files.


7083 RCI_HF_FREQUENCY wert_04
7083 UGDO_COUNTRY USA
7083 VAM_CCM_COOLANT_TEMP aktiv



Coding this was a steep learning curve for me and I was lucky to have some help and I've since coded a few things to my M850i. Hope this was informative.

[BeeMdblU]

Nice Project, thank you for posting

[FBMWWINS]

It's always nice to get some coding information (or retrofit for that matter) generally speaking especially on a model that is still "young" and about which there is less coding information around when compared to others.

[LBSypher]

I'm attempting to do the same thing minus the switch and rear fog lights. I PM'ed you about it BigMofoFrog.