As above, use a 12 volt test light if you don't have a multi meter. TURN BAD SWITCH - ON. Clip ground lead to battery NEGATIVE post.
Press probe on Battery side of contact on breaker, then Switch side of breaker. If tester lights on battery side of breaker power to it is ok. If no power, power from panel positive Bar to breaker is bad or connection is broken at bar.
Otherwise there's a break or SHORT between the breaker and item being powered or a ground wire of or shorted at the item or up the line to the negative switch panel bar.
NOTE: on some switch lighted switch/fuse panels, the power runs through the light first in series then onto the switch. So if the light burns out no power can get to the switch after the breaker. Good luck