Brake lights do not work!

I have a 2000 XLT Explorer, and The upper Brake light works, but the main brake lights dont! Any suggestions on how to fix this, or diagnose the problem?

Maybe check for ground on the lower brake lights. You might not have a complete circuit, which would not affect the upper light. I don't think it could be the fuse as they all are on the same one. If you've got a meter, you can also check for shorts in the wires supplying the brake lights.

I have the same exact problem and since the lower brake lights stopped working, the auto lock has stopped working as well. I have replaced the bulbs and still nothing. I heard on another forum that the "light out module" needs to be replaced. I have no idea where this is, or if it is even the problem, does anyone have a suggestion