As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CABIN EMERG LIGHT: EMER LIGHTS WILL NOT ILLUMINATE IN THE "ON" POSITION, BUT THEY DO ILLUMINATE IN THE "ARM" POSITION. WE RAN THE APU FOR 20 MINUTES AND THEN SHUT DOWN AND ATTEMPTED TO TEST AGAIN AND SAME ISSUE. AFTER FURTHER CONFERRING WITH MCC WE RAN THE APU FOR ANOTHER 30 MINUTES WITH THE SAME RESULT.