As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT DC GEN CAUTION LIGHT ON INTERMITANTLY RESETS AFTER 10-15 SECONDS. AIR RETURN TO MSP. REMOVED AND REPLACED LEFT AC GEN GCU DUE TO DISCREPANCY IN COMMUNICATION WITH MXC/MX AND FLT CREW. P/N 51634-002, S/N OFF 97035, S/N ON 97031 IAW AMM 24-20-10-2. REMOVED AND REPLACED LEFT DC GCU IAW AMM 24-30-10 51539-007B, S/N OFF 98657 S/N ON 98114. OPS CHECKS GOOD.