I don't know much about electrical systems, so this might be a really simple issue for some of you but it has me scratching my head. And it caused my son to get pulled over, which resulted in a 3x fix-it ticket for 1) The brake light, 2) modified exhaust and 3) no front plate.

Here's the issue:

Right side brake light doesn't work.

Some issues:
- Left side works fine
- Replaced the bulb. No change.
- Realized that the same bulb is used for turn signal and it works performing that duty!
- Hazard lights (including the brake light bulbs) are working fine.
- It worked until recently
- I will go through the fuses tomorrow when it's light, but I assume it shares a fuse with the left side, no? Again, the left side is working.

Any thoughts/ideas would be most welcome!

Edited May 8, 20186 yr by Grubb240Z
Added more info to my description

Most likely the emergency lights switch..  your brake wiring is going through this switch..  (an American car has a 9 (!)pole  em.switch where a euro style has only three 3 !!!  )

The ground wires for all the lights in the back are incorporated into the sockets and it's not uncommon to find them corroded or pulled out enough so they are not making contact anymore. But you say the signal is working so it might just be the brake light filament that has blown in that bulb, if you can't see a broken filament in the bulb, switch the right and left bulbs to test it.

Hope it's a simple fix.

The brake light circuit is interrupted at the turn signal. It is after the hazard light switch. Since you said your right turn signal works, it is most likely the turn signal switch.

https://fiddlingwithzcars.wordpress.com/2012/12/04/turn-signal-repair/