As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE FINISHING PRE-FLIGHT WITH 'BEFORE START CHECKLIST' COMPLETED 'TO-THE-LINE' THE AFT PEDESTAL FIRE/OVERHEAT FAIL LIGHT WAAS ILLUMINATING INTERMITTENTLY. THEN WE SMELLED AN ACID BURNING SMELL FOLLOWED BY A VISUALLY VERIFIED FIRE (FLAMES) INSIDE THE AFT PEDESTAL. WE IMMEDIATELY SHUT DOWN POWER TO THE AIRCRAFT, STOPPED LOADING, AND CALLED AIRCRAFT MX AND ARFF. INSTALLED NEW PANEL AS PER AMM 26-11-02-4. OPERATION CHECKS NORMAL. A/C OK FOR SERVICE.