As mentioned this is not rocket science! Do the basics and troubleshoot the tail light connection at the tail light. Check to see if you have power to the power lead at the tail light socket? If so great it is most likely the bulb(s) are faulty. If that is not the case then you have a possible ground issue so clean up the ground wire. You might even have rust or corrosion in the socket itself or the wires themselves from possible moisture getting in. You will then have to determine why and how moisture is getting in? Obviously if you have power to the tail light socket your fuse is fine. If you want to be sure then replace the fuse first, again a basic step in troubleshooting your "electrical problem"!