What was found
LEFT PITOT LIGHT ILLUMINATED IN FLIGHT. QRH COMPLETED. RETURNED TO DTW. REMOVED AND REPLACED 5HG CURRENT MONITOR, PN ON/OFF 006WS00 SN 1581, SN OFF 1627. LEFT PITOT TUBE PN ON/OFF 856ML3, SN ON 214837, SN OFF 215686. ALL CHECKS GOOD IAW SF 340 M/M CH 31 AND 34.