As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW STATES THAT RT PACK OFF LIGHT ON WHEN ENGINE BLEEDS ARE ON. PACK RUNS OK WITH APU BLEED. RT PACK OFF LIGHT ON WHEN ENGINE BLEEDS ARE ON. PRV VALVE REPLACED, NO HELP. CONTINUING TO TEST. FOUND SENSE LINE AT HPRSOV NOT TOTALLY TIGHTENED. ADJUSTED AND RAN ENGINE TWICE, FOUND RT PACKS WORKS OK.