This was previously discussed in a post: http://www.hyundai-forums.com/lf-20...018s-front-door-reflectors-ever-light-up.html
I was the one who asked the door courtesy lamp/reflector question.
I jumped into removing the door panel and found the door courtesy lamp lenses have the mounting hole for a twist-in bulb socket but there is no dedicated courtesy lamp wiring from the main harness out to either door (the BCM's connector cavities for the courtesy lamp control wires aren't populated).
I did find that there remains a dedicated circuit out to each door (used for smartkey's welcome LED light in the handle on prior years) that's controlled by the BCM. On 2018's, wiring exists but circuit not used.
The problem though is if you tried to tie the courtesy lamp bulb into this circuit, the courtesy lamps would only illuminate when the locked vehicle is approached with the smartkey. Wouldn't serve for the purpose of wanting courtesy lamps illuminated when the individual door is opened (puddle lamps).
However, I gained access to the BCM (behind the heater/AC/ventilation control panel, only held on by 10 clips) and noted that I should be able to remove the smartkey door LED wire from its original BCM connector cavity (A15) and tie it in with the cabin lamp control wire in cavity A01.
In essence, the courtesy lamps would both illuminate when any door is open and would fade out with the cabin lamps.
My only concern is that the smartkey LED wire size from BCM to door handles is AWG-22 (~5 amps max). I don't know what bulb is called for in the owner's manual for those courtesy lamps.
I figure if the amps drawn by the two bulbs in parallel is greater than 5 amps, I could use the AWG-5 wire in the door as the 'base' control on a PNP transistor setup, tapping the 'always HOT' AWG-16 power window wire for the 'emitter' and the courtesy lamp bulb wire as the 'collector'.
Anyway, that's where I was in the project when I dropped it to work on the trunk lid-mounted tail lamps illuminating with the brake lamps (without cutting any wires) project.:shades: