How do you troubleshoot the tail lights not working on a 99 Toyota Corolla?

The best way to troubleshoot why the taillights are not working on a 1999 Toyota Corolla is to first check all of the bulbs to see if one is burned out. Then check the fuses to see if there is a blown fuse. If the problem is still not found, a code reader in the ECU (computer) might show a code that will help find the problem.