What was found
PILOT REPORTED AT CRUISE FLIGHT, AT APPROX 6000 FT, DURING STAGING FLIGHT, THE CREW ADVISED THE FIRE DETECTION SYS ACTIVATED INTERMITTENTLY IN FLIGHT. THE CIRCUIT BREAKER WAS RESET AND THE SYS WOULD DEACTIVATE FOR APPROX 10 MINUTES AND THEN REACTIVATE. ARRIVED INTO DESTINATION WITHOUT INCIDENTAND NO EVIDENCE OF FIRE WAS NOTED AFTER THE ACFT WAS SECURED. MX TROUBLESHOT AND INSPECTED FIRE DETECTION SYSTEM AND FOUND DEFECTIVE TEST SWITCH. MX R & R DEFECTIVE TEST SWITCH IAW MM 26-10-00, ALL GROUND OPS AND FUNCTIONAL CHECKS WERE GOOD.