As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING LINE CHECK, MAINTENANCE FOUND THAT THE EMERGENCY PATHWAY LIGHTING IN ROWS 13-15 OF THE CABIN WERE INOPERATIVE. MAINTENANCE FOUND IMPROPER INSTALLATION OF THE BATTERIES. BATTERIES HAD BEEN INSTALLED BACKWARDS. REINSTALLED BATTERIES AND OPERATIONAL CHECK WAS GOOD. (A)