Interior lights flickering... UNWANTED DISCO!

[MBellRacing]

Hey everyone. I am back to the darkside after going Audi/VW for a little while. In short, my parents owned a 4.8iS when I was in high school and it was the best SUV I've ever been lucky to spend time driving. Finally bought another one the other day as a daily driver. Overall, really good condition. However...

The passenger front door puddle light and the left rear seat light are flickering. All other interior lights do just fine. They have all been upgraded to white LED. Where should I look first for a loose connection, and/or is it possible the previous owner's LED conversion is just no bueno?

Any help appreciated! Not super afraid of valve seals or coolant pipes, but WIRING scares the poop outta me in this generation car!