What was found
ONCE AIRBORNE GEAR HANDLE REMAINED LOCKED IN THE DOWN POSITION. CREW UNABLE TO RETRACT LANDING GEAR. JACKED AIRCRAFT CONNECT MULTIMETER TO P65 CHECK INFLIGHT STATES FOUND SWITCH OPEN. AFTER FURTHER TROUBLESHOOTING FOUND SW (S83) 180 DEGREES OUT. REMOVED ARM AND ADJUST SWITCH TO CORRECT SETTING. PERFORMED RIG ADJUSTMENT AND OPS CHECKS SYSTEM OPS CHECKED GOOD IAW CESSNA 560 MM 32-61-00.DOWN JACK AIRCRAFT.