As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER TAKEOFF THE FLIGHT CREW NOTICED THAT THE NOSE GEAR RED AND GREEN LIGHTS STAYED ON AFTER GEAR RETRACTION. A NORMAL LANDING WAS MADE. CLEANED NOSE GEAR PROXIMITY SWITCHES AND REPLACED THE LANDING GEAR ACCESSORY UNIT. OPS CHECK NORMAL IAW MM. THE AIRCRAFT WAS RETURNED TO SERVICE.