One brake light on left botton and one on right top is out. The bulb and fitting have been tested and work. Could the problem be a fuse. Help!!!

That makes no sense! The bulb and fitting 'have been tested and work'.... So they have VOLTAGE and GROUND? explain HOW you are 'testing' please. Is it a printed circuit on the tailight assembly? So , when youi step on the brake pedal , something DOES work ?? The switch is good , and unless there are multiple fuses or something else in the circuit (from switch to bulb(s) then you have broken wire(s)?Test harness.....

Sounds like you need a taillight harness repair kit. It is a $20.00 kit on eBay. The lower brake light (the triangle) only work if the upper larger brake lights fail, which is a common problem.