What I want: I'd like the rear fogs to work as extra brake lights. Been doing a lot of reading the FAQ section and the thread on coding here, but haven't found the answers I'm looking for.
What I have: 2016 MCS. No rear fog button. I've installed US spec UJ Tails, with this coding:

• BL_R_IS_LED = aktiv
• BL_R_WARMUEBERWACHUNG = nicht_aktiv
• BL_R_KALTUEBERWACHUNG = nicht_aktiv
• BL_L_IS_LED = aktiv
• BL_L_WARMUEBERWACHUNG = nicht_aktiv
• BL_L_KALTUEBERWACHUN = nicht_aktiv

• MAPPING_BREMSL_2_L_OUTPUT = fra_h_l
• MAPPING_BREMSL_2_R_OUTPUT = fra_h_l

The lights work with no malfunctions. When brakes are applied while the turn signal is on, the turn signal (the -l and l- sections) blinks instead of just a constant brake light.
If I change the MAPPING_BREMSL_2_x_OUTPUT = to nsl_r as suggested in the coding thread, the fogs come on as brake lights, but the vertical and horizontal brake lights in the tails don't light up. Basically, I move the brake lights from the tail lights to the fogs. I've seen the workarounds for the standard lights have both, but that doesn't work with the UJ tails. Can anyone point me in the right direction? I can't be the only one who would like to have it set up that way.

 

I have a 2019 with the UJ tail lights and was able to enable the rear fog lights as brake lights. I also don't have a fog light switch. Both the UJ and fog lights light up on brake application. Only the UJ blinks with the turn signal.

I followed these instructions:

Rear Fogs as Brake Lights: (This hasn't been checked on a car w/rear fogs working)

BDC_BODY
3065 LceLampMapping4, ED
Funktionen
MAPPING_BREMSL_2_L_OUTPUT
Switch to this
nsl_l (this is the rear fog light choice)

You need to do this for right and left. Above is for left,
For RHS just change the l to r

MAPPING_BREMSL_2_R_OUTPUT
nsl_r__________________

 

When I tried that, I lost brake lighting on my UJ lights. Rear fogs worked as brakes, but not the taillights.

 

No one else has tried this?

 

Hi SmittyRN,
I also have the same situation. I just upgraded my 2016 F55 to UJ tail lights (Euro-spec with ambers) and then Bimmercoded my rear fogs to hopefully work IN ADDITION to the new brake lights. I got the fogs to work as brakes, however they REPLACED my main brake lights. Then I restored it back as before (with dead fogs)...I wondered if you found a resolution since your post?
Many thanks, Doug

 

That's what happened to me. Talked to a dude in the know, because of how the signals travel (or something like that) it can't be done. Not by programming, at least. Oh well.

 

I bought a set of Helix UJ tail lights. Was told it was euro style. I have coded the rear fogs to come on as brake lights. The info above was what I used for coding.

 

That's not gonna work for OEM Union Jacks, unfortunately.

 

I just connected mine yesterday, US, UJ, LED's on my '15 S, hard wired. IJDMtoy makes a kit that I bought but ended up not using. Their line taps are junk. It took about 2 hours to do and you have to drop the rear valance/bumper. I found some great taps and connectors on Amazon and LED bulbs that replace the fog bulbs. You need a voltage meter. The parts, including the wire (20g), plastic wire wrap, extra connectors, LEDs, runs about $50. I'll post a procedure if interested. Should work on LCI UJs as well.

 

I actually have this same exact problem. I have the UJ lights from FunFob. I've seen videos of people with the same setup and they've managed to get the rear fogs to work with their primary brake lights. When I asked them how they did it I just got redirected in circles because nobody wants to be liable for any errors. 😡

My theory is that the aftermarket ones are read by the ecu as secondary brakes so that when you choose the nsl (rear fog) option it changes that to the secondary brake light. I also have no idea what I'm talking about. But just a hunch.