What was found
AFTER TAKEOFF, LT GEAR UNSAFE DOOR, RED, STAYS ILLUMINATED AND GEAR HANDLE RED LIGHT STAYED ON. NOSE AND RT GEAR ALL SHOWED RETRACTED AND DARK. AT APPROXIAMATELY 1000 FT ABOVE FIELD ELEVATION, MAYBE 15-20 SECONDS, LT GEAR UNSAFE LIGHT, RED, AND GEAR HANDLE UNSAFE LIGHT WENT DARK, ALL INDICATIONS NORMAL FOR REST OF FLIGHT, NORMAL GEAR EXTENSION. LANDING UNEVENTFUL. CHECKED PSEU FOR FAULTS. NONE FOUND. REPLACED LT MLG NR 1 AND NR 2 DOWNLOCK PROX SENSOR HARNESSES. CYCLED MLG, OPS CHECK GOOD. ACFT RELEASED FOR CHECK FLIGHT. CHECK FLIGHT GOOD. RETURNED TO SERVICE.