As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
EXIT LIGHT ON FLOOR BY SEAT 22L FLASHING. FUNCTIONED LIGHTS THRU SEVERAL CYCLES, CHECKED CONNECTERS AT M1554 BATTERY PACKS, ALL FOUND NORMAL. FOUND EMERGENCY LIGHT SWITCH ON OVERHEAD PANEL LOOSE, TIGHTENED SWITCH UNABLE TO PRODUCE FAULT ON GROUND.