As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT 6581 - MEX-CUN - AIRCRAFT RETURNED TO GATE, AC CROSS TIE NO TEST. DURING REVISION WAS DETECTED ACTR LIGHT AND APU PWR AVAIL LIGHTS ON. THE GCU AND BCU WERE REPLACED IAW MM 24-20-04/08 AND ENGINES AND GENERATION SYSTEM WERE TESTED, ALL CORRECT. (M)