As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DTW - FLT 874 - AT CRUISE, RECEIVED THE AC CROSSTIE LOCKOUT LIGHT, LT FLIGHT FAULT AND LT GEN OFF LIGHT ON AFTER REINSTALLING POWER TO THE LT AC SYSTEM WITH THE APU PER OUR QRH. UNABLE TO RESTORE LEFT GENERATOR POWER. REMOVED AND REPLACED GENERATOR CONTROL UNIT. TIGHTEN ALL FIREWALL GEN CONTROL AND POWER CONNECTORS. OPS CHECK NORMAL ENGINE. (M)