Brake light issue

I'm assuming the left side is working? If it is working, that would eliminate a fuse issue. Chances are that the vehicle "may" have been in an accident and repaired in that quarterpanel. It's possible the wires are not connected at the quick connect to the wiring harness. Those light assemblies are fairly straight foreward to remove. If you aren't confident, check out a repair manual from the library. Remove the light as a complete assembly, check the wiring connection to the tail light harness. If that isn't connected, plug it in and recheck the lights before re-installation. (CAUTION!!! If there is evidence of a repair to the quarter panel and the light is unplugged, IT MAY HAVE BEEN INTENTIONAL! Unfortunately, some used cars that have accident related electrical issues are by passed to get rid of the car. So..if you blow a fuse right away, there is a short that the previous owner failed to correct. If it is already connected, check the wires for damage or a faulty connection where the plug mates to the harness. If that doesn't solve the problem, you'll have to trouble shoot the electrical wiring from the light back towards the battery. I hope this helped!