The inside passenger side brake light is not working. However the bulb still works as far as running lights go. All 3 other bulbs work correctly. Wiggled around the wires without any luck, anyone have some guidance?

 

Could be an issue with the contact on the bulb to harness. A friend of mine kept having issues with 3/4 taillight only lighting up. It seemed the area connecting the harness to bulb was corroded.