As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
GEAR WOULD NOT RETRACT ON T/O FROM KONA. ISOLATION VALVE LIGHT CAME ON AND GEAR HANDLE COULD NOT BE RAISED PAST THE OFF POSITION. WITH GEAR HANDLE DOWN, WE HAD NO GEAR LIGHTS. VISUALLY CHECKED GEAR DOWN AND LANDED AT KONA. INSPECTED LANDING GEAR SYSTEM AND FOUND LANDING GEAR LIGHTS CIRCUIT BREAKER OPEN. RESET CIRCUIT BREAKER AND CHECKED OK. NO FAULTS NOTED. AIRCRAFT RETURNED TO SERVICE.