You have begun the process of diagnosing the problem by verifying that the fuses are good. Isolate each component in the circuit to check it's function. Start with the battery, terminals, power the wiring with a fresh battery and connect a 12v light source, check switch continuity, then the light base and bulbs. Clean as you go and secure each connection (paying close attention to the grounds). Do not attempt to verify the status of two or more elements in the circuit at one time - remember Murphy's Law. In my opinion, Murphy was an optimist.
