As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE TROUBLESHOOTING SCHEDULED MEL 6215944 FOR LEFT O/B LANDING LIGHT POPS C/B WHEN TURNED ON. FOUND BURNT WIRING WHERE IT GOES INTO A CONDUIT OVER THE NR 1 ENG PYLON. WIRING CHAFED AGAINST CONDUIT CAUSING IT TO SHORT OUT. EVENT BASED TECHNICAL RESPONSE INITATED BY MAINT CONTROL AND ENGINEERING.