As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: AFTER ENGINES SHUT DOWN AT GATE CABIN CALL LIGHTS ON CA AND FO ACP BEGAN FLASHING WITHOUT BEING CALLED, ALONG WITH AN UNCOMMANDED EVACUATION HORN. EMERGENCY CALL SWITCH LIGHT ON OVERHEAD PANEL. AND FAULT LIGHT ON FAP CIDS PANEL. MAINTENANCE REPLACED #1 CIDS DIRECTOR PER AMM 23-73-34 AND ACCOMPLISHED A SATISFACTORY OPERATIONAL CHECK.