As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING AN OVERNIGHT LINE CHECK THE AFT MOST 2 SLIDE ILLUMINATION LIGHTS ON THE ACFT RT WOULD NOT TEST. MX FOUND THE ASSOCIATED POWER SUPPLY MODULE AND BATTERY TO BE DEFECTIVE AND REPLACED THEM. SYSTEM OPS WAS NORMAL AFTER THE POWER SUPPLY AND BATTERY WERE REPLACED.