2015 Genesis Tail/Break Light Issue

[Stix]

I love my 2015 and still runs like new. But my passenger side - inside trunk lid tail light that also handles the brake light only works whe the brakes ARE NOT applied. Anybody else ran into this and how you resolved it? I already replaced the light assembly with a OEM light, the problem is exactly the same. I am now leading towards a possible fuse or forbid the cabling? Any feedback is appreciated!

 

[joegr]

On most cars, that symptom is caused by the ground to the assembly being missing (disconnected). If the ground is going to a nearby stud, take it off, sand it a little, and re-attach it.
What happens is that current flows through the tail light filament and then on through the brake light filament and finds a ground somewhere else, like the other side brake light. Since the brake light filaments are so much lower resistance than the tail light filaments, you can only see the tail light filaments glowing (slightly dimmer than it should be). When the brake is pressed, the current from the brake light filament doesn't have a low enough resistance route to ground for it to light up. Fix the ground, and all should work correctly.

 

[Stix]

Sounds like a plan, will give it a go. Thanks joegr!