What was found
AMBER LT DOOR & RED LEFT & GEAR HANDLE ILLUMINATED DURING CLIMB OUT, AFTER GEAR WAS SELECTED UP. JUST PRIOR TO DOING ALTERNATE GEAR EXTENSION, THE LIGHTS EXTINGUISHED ON THERE OWN. ALTERNATE GEAR EXTENSION & LANDED WITH NO ISSUE. DIVERTED. LANDING UNEVENTFUL. ADJUSTED THE LT UPLOCK PROXIMITY SENSOR AND VERIFIED THE PROXIMITY SENSOR CONNECTOR WAS SECURE. REMOVED AND REPLACED THE INLINE FILTERS IN LT GEAR SOLENOID SEQUENCE VALVE. OPS TEST OF LANDING GEAR PRIMARY EXTENSION/RETRACTION SYSTEM WAS GOOD. COULD NOT DUPLICATE THE DISCREPANCY. AIRCRAFT RETURNED TO SERVICE.