As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE TAXIING AFTER LANDING AND APU START WAS INITIATED. AFTER APU START THE APU GEN FAILED TO CONNECT. CYCLES OF THE APU GEN SWITCH FAILED TO CONNECT. SUBSEQUENT TROUBLESHOOTING REVEALED EVIDENCE OF "HOT SPOTS" IN THE LH MAIN ELECTRICAL BOX PANEL. SPECIFICALLY AROUND APU CONTACTOR AND ASSOCIATED WIRING.