What was found
UPON DEPARTURE FROM ADDISON TX LANDING GEAR HANDLE WAS UP BUT RED LIGHT WAS ILLUMINATED. GEAR APPEARED TO NOT HAVE RETRACTED. GEAR SUBSEQUENTLY RETRACTED, BUT UPON FURTHER TESTING WOULD NOT EXTEND. DIVERTED TO SAN ANTONIO SAT AND USED ALTERNATE GEAR EXTENSION. THE NLG AND LT MLG SHOWED DOWN AND LOCKED. RT MLG DID NOT SHOW CORRECT DOWN AND LOCKED INDICATION, NO GREEN LIGHT. PERFORMED CHECKLIST AND RESET LANDING GEAR CIRCUIT BREAKER. ALL THREE DOWN AND LOCKED LIGHTS ILLUMINATED, AND TOWER FLYBY CONFIRMED GEAR APPEARED NORMAL. GEAR FUNCTIONED NORMALLY. FOUND RT MAIN LANDING GEAR SQUAT SWITCH DISCONNECTED DUE TO MISSING SAFETY PIN AND NUT THAT RETAINS CLEVIS PIN FOR SQUAT SWITCH ACTUATOR.