As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
INFLIGHT AT FL350, BOTH LT & RT UTILITY BUSS AMBER LIGHTS CYCLED ON AND OFF 4 TIMES IN A 30 MINUTE PERIOD. DIVERTED BACK TO DEPARTURE. TROUBLESHOT IAW FIM 24-20-00, FOUND BPCU INTERMITTENT. R & R BPCU IAW AMM 24-41-03-404-008. UTILITY BUSS SYS OPS CHECKED NORMAL IAW AMM 24-22-00. ACFT OK TO CONTINUE.