As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ELEC LIGHT ILLUMINATED ON OVERHEAD PANEL DURING PREFLIGHT. GROUNDED - YES. REFERENCE FIM 24-31 TASK 801. PERFORMED ELECTRIC LIGHT BITE TEST. FOUND SPCU INOP FAULT, CYCLED SPCU C/B'S RE-PERFORMED BITE TEST, FAULT CLEARED AND ELECTRIC LIGHT WENT OUT.