Every bulb on the car works except the passenger side rear tail light, backup light.

What do you sugggest?

I currently repair flat panel computer monitors, burning and resoldering bad caps on printed circuit boards, so I know a few things about boards.

Do I need to replace the entire rear tail light assembly, or can a single bulb be replaced. I did find some single HIB on line.

I can see the wiring plugin to the tail light assembly by removing the trunk panel that covers it on the back from the trunk.