'90 300E.....

Ok, here's the latest friggin electrical problem. The passenger-rear side marker light would randomly not work for the past week(indicated by the bulb-warning light), and then went out completely. I changed the bulb for it (with the correct type) and it still does not work. I even opened up the tail-light connection plug and cleaned it out a little and still nothing. Any ideas guys? - Mike

(By the way, I am just one more step closer to setting this car on fire for various reasons)