If someone can help thank you

I have a 99 911 cab. Right rear running lights dont work but brake lights do. I changed the harness and still not working Tested the tail light assembly on passenger side and it works any idea??

 

Not sure if this will help. I would check to make sure there is no corrosion on the bulb and in the socket, then use a volt meter to ensure you have current going into the socket. Could be a bad fitting bulb or something preventing the electric from getting to the fixture.

 

If you have already tried to track down the open wire and are at a loss, you can always run another running light wire from the left side.