As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMB THE CREW RECEIVED A WARNING THAT THE LT MAIN GEAR DOOR LIGHT WOULD NOT EXTINGUISH AND THE LANDING GEAR CAUTION LIGHT WAS ILLUMINATED. DECLARED AND EMERGENCY AND RETURNED TO FIELD. GROUND MX TRACED THE ISSUE TO A BAD PSEU. ON CHANGING THE PSEU, PERFORMED AN OPS CHECK THAT PRODUCED SATISFACTORY RESULTS.