HELP! no instrument cluster illumination
 

I have a 2001 F150 Lightning. For about 4 years now I have had no illumination with the instrument cluster. Have checked fuse # 18, switch, and pulled out cluster to check bulbs and circuit board, still no solution. Replaced fuse, still no power. After replacing fuse, checked both sides of fuse while installed with meter and determined there is no power on the fuse nor to that fuse outlet. Checked both sides of outlet without fuse, no power either???Does anyone know what the problem is or have a solution?