As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING THE EMERGENCY EVAC SYSTEM CHECK, WITH THE CKPT SWITCH ON ALL HORNS OPERATE OK. WHEN THE HORN SWITCH IS PUSHED AT DOOR 3L HORN FAILED TO SHUT OFF. THE REMAINING HORNS WENT OFF OK. :NEED TO ID SW # ADJ SWITCH. HORN SHUTS OFF WHEN SWITCH ACTIVATED AT 3L.