I searched and found various issues but none like this. My interior lights don't work obviously... It's not the bulbs because I've confirmed they still work. Tt can't be the fuse since they deliver 12v if I ground the multimeter to the screws that hold the assembly in place. The only thing I can think of is that both grounding terminals are bad but I can't get the assembly off to confirm this... Please help.

 

Nevermind... Gave the switch a little pry and it popped out. Turns out the switches contacts were a little corroded so I just cleaned them up and smeared some dielectric grease on them and it works like a champ.

 

Hmm is the middle a "door" open light option?
When I put it in the middle or far right it stays on even with the doors closed. Far left is off.
(Switch on the middle top lights by rearview)

 

Check your top for leakage. it'll corrode again if you leave it.