No driver-side reverse light, other driver-side lights in the tail light are dim

This is a bit of a headscratcher that I've been dealing with for some time. It's not a problem with the bulbs or the tail light assemblies as all of that has been replaced with leds and aftermarket tail lights without a change in behavior.

The passenger side works perfect however all the lights on the driverside tail light assembly are dimmer and the reverse light doesn't come on at all.

Any thoughts?

 

Bum ground would be my guess.

 

I had a similar issue, was due to water in my engine fuse box.

Pop the hood on a sunny day open the box point a fan at it for several hours then throw some desiccant packs in there.

 

Any idea where that specific ground is? I found reference online but not sure where to find it.

 

No lack of sun here. I'll try it to be sure - I may even have compressed air around to give it a few blasts first.