Headlights, brake lights and fuel gauge are not working

My wiring diagrams are somewhat incomplete so I cannot see what all these circuits have in common. If all the bad circuits stopped operating at the same time, check if the horn works. If it does not, check for twelve volts on fuses 7, 8, 9, and 10. Fuse number 7 might be not used. If you find zero volts on all those fuses, we will need to figure out where to go next.