[vgore]

After searching the forums, I could not find a definite answer to this question. Has anyone done this mod?

[oranga]

I think it would be pretty straightforward, you basically have to code the rear fogs to be treated as brake lights and come on when the brake switch is depressed.

Take a look at the REM (rear electronic module) section in the attached lamp mapping document, and read thru this thread: https://f30.bimmerpost.com/forums/sh...d.php?t=911250

But i THINK what you'd want to do is change

MAPPING_BRAKEFORCED_2_L_FUNCTION = 0C (Brake)
MAPPING_BRAKEFORCED_2_L_OUTPUT = 1C (Rear fog L)
MAPPING_BRAKEFORCED_L_PWM_LEVEL_1 = 13.5V
MAPPING_BRAKEFORCED_L_FIXED_PWM = 00 (pwm)
MAPPING_BRAKEFORCED_L_PRIORITY = 02

MAPPING_BRAKEFORCED_2_R_FUNCTION = 0C (Brake)
MAPPING_BRAKEFORCED_2_R_OUTPUT = 1D (Rear fog R)
MAPPING_BRAKEFORCED_R_PWM_LEVEL_1 = 13.5V
MAPPING_BRAKEFORCED_R_FIXED_PWM = 00 (pwm)
MAPPING_BRAKEFORCED_R_PRIORITY = 02

An explanation of what is happening:

Lines 18 and 19 on the lamp mapping diagram show that there are 2 unused functions that are labeled for brake force. We know they're unused because the output is set to 'off'. Technically we could use any such function that is set to off, since there are quite a few of them.

When we set

MAPPING_BRAKEFORCED_2_L_FUNCTION = 0C

we are saying this function is active when the brakes are on. We know the value for brakes is 0C because lines 7-8 correspond to the brakes and their value is 0C.

And when we set

MAPPING_BRAKEFORCED_2_L_OUTPUT = 1C (Rear fog L)

we are saying that we want the left rear fog light to come on. Again, we know the value for the rear fog lights is 1C because in line 30, the value is for left rear fog is 1C. The other lines are just settings copied over from lines 30 and 31 which normally control these lights, so we wont mess with them.

Good luck!