For those messing with the HUD turn signals, an interesting thing I have found is that somehow the "profiles" are linked to whether they work or not. If you program them and they seem to only work some of the time, go into the profile menu and switch to one of the other profiles (even if still named '----' by default). You'll find one where it is 'working'. Unsure if this will happen with any other settings, but figured I would share my experience.
HUD TURN SIGNALS
KOMBI -> 3008 -> HUD_PIA_BLINKER -> aktiv
KOMBI -> 3008 -> BLINKER_HUD_ENABLE -> aktiv
HU_NBT -> 3000 -> HUD_TURNSIGNAL -> aktiv
Display turn signal indicators in the HUD