As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APU FAULT LIGHT CAME ON WHEN WE TRIED TO START THE APU AT THE GATE PHNL. GROUNDF EQUIPMENT LIGHT WAS FLICKERING AT EVERY STATION WHEN CONNECTED TO GPU. PERFORMED OPS CHECK ON APU PER AMM 49-11-00. ABLE TO START APU AT FIRST ATTEMPT, NO TROUBLE FOUND.