As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
UPON CREW PERFORMING FIRE TEST FOR PRE-DEPARTURE CHECK, APU FIRE WARNING HORN CIRCUIT BREAKER POP OUT. FIRE WAS SHOWING PASS. ALL COCKPIT AURAL WARNING AND INDICATION NORMAL DURING TEST. IAW GMM 03.05.01.03 DEFERRED FAULTS-ADDITIONAL ACTION WDM 49-61-21-1 CB C1144 @ P6 PANEL PULL COLLAR BREAKER AND PLACARD INSTALLED.