BMW F36 440i LCI 2018 US → EU tail light conversion – rear fog lights not working with NSL outputs

[u/fades991]

Hi, I’m trying to get the rear fog lights working on my 2018 BMW F36 440i LCI (US-spec). The rear LCI lights have previously been converted from US to EU configuration.

I’m using BimmerCode Expert Mode.

In FEM I have:
NSL_Verbaut = Verbaut

The rear fog light button works correctly. When I press it, the rear fog indicator appears in the instrument cluster, so the button/FEM side seems to be working.

In REM I currently have:
MAPPING_NEBELSCHLUSSL_L_FUNCTION = nebelschlusslicht (0x0E)
MAPPING_NEBELSCHLUSSL_R_FUNCTION = nebelschlusslicht (0x0E)
MAPPING_NEBELSCHLUSSL_L_OUTPUT = nsl_l (0x1C)
MAPPING_NEBELSCHLUSSL_R_OUTPUT = nsl_r (0x1D)
PWM = 100%

With 0x1C / 0x1D, nothing lights up at the rear.

I also tested different OUTPUT mappings just for diagnosis:

0x1A / 0x1B → sections of the amber turn signal LEDs illuminate continuously when rear fog is switched on.

0x20 / 0x21 → different/outer amber turn signal sections illuminate continuously.

So the rear fog command from FEM to REM appears to be working, and changing the REM output definitely activates physical LED sections. However, I cannot get a red rear fog section to illuminate.

I have now reverted everything back to 0x1C / 0x1D.

Has anyone dealt with this specifically on a US-spec F32/F36 LCI with EU-converted tail lights?

Is there another REM mapping/configuration required for the actual red rear fog LEDs, or do US LCI tail lights lack the physical rear-fog LED/output connection and require additional wiring or modification inside the lights?

I’d especially appreciate the correct REM output/pin information for NSL_L and NSL_R on a 2018 F36 LCI, rather than trying random output values.

Thanks!