Arrived at customer's house and made our way to the main panel. Checked for tripped breaker did not see any. Went into attic and looked for wires connecting to GFCI outlets for testing, no break in the wires. While tightening connections in main panel we noticed that a breaker on the generator panel was tripped. When reset the garage had power again. We also looked at customers bedroom fan because the lights were not coming on when the switch was flipped. We checked the connections on the switch and found them to be loose, once tightened the lights functioned properly.