As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APU FAULT LT ILLUMINATED. GROUNDED - YES. REMOVED AND INSTALLED NEW SCU PER B737-800 AMM 49-41-61/401, OPS NORMAL. REMOVED AND INSTALLED NEW SPU PER AMM 49-41-71/401, OPS NORMAL, NO FAULTS FOUND. PER TECH SVC REQUEST DUE TO HISTORY REPLACED APU ENGINE HARNESS PER AMM 49-11-01. ALL OPS NORMAL GROUND VERIFICATION CHECKS GOOD.