Let and idiot borrow the car, it comes back with blown tail lights. Ive changed all the bulbs and the brake light fuse.

3rd brake light works (one inside car above trunk)
turn signals work
when you turn on the front headlights (the rear brake lights light up)
reverse light works too
license plate lights dont work but they are prolly blown havent changed them yet.

So my question is, where do I look. When I hit the brakes only the 3rd brake light comes on, but I know all the bulbs work because they light up when I turn my headlights on. They just dont light up when I come to a stop.

 

Manage to get the right brake like working, ive concluded that the circuit board on the left prolly needs to be replaced, but since I have 2 brake lights out of 3, thats good enough for me. Plus it lights up at night so whatever.