As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FOUND THERMAL SWITCH PN 512T130B150001 INSTALLED. REMOVED SWITCH AND INSTALLED PN GAS850DF512-250 REV B. THIS SWITCH CORRECTED PROBLEM. THE REMOVED SWITCH CAUSED (FIRE WARNING LIGHT FOR THE LEFT AFT DUCT) TO COME ON. NO LEAKS NOTED. THE SWITCH REMOVED WAS NOT CORRECT PART NUMBER.