As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: PILOT REPORTS GEAR WARNING HORN AND RED GEAR LIGHTS ILLUMINATED AT 5000FT, LVL CHANGE POWER TO IDLE (ADDED POWER THEN WAS OKAY), UPON LANDING THE 50-20 FOOT CALL OUT DID NOT WORK. L/G POSITION INDICATING AND AURAL WARNING CHECKS OK IAW AMM 32-61-00-009. REPLACED ENHANCED GROUND PROXIMITY WARNING COMPUTER IAW AMM 34-46-01. NO FAULTS NOTED.