What was found
AFTER TAKEOFF, GEAR HANDLE UP GAVE RED LEFT MAIN INDICATION ON F/O PANEL AND UP FRONT. RAN RED TAB, NO HELP. CHECKED WIRING INTEGRITY FROM S3-682 TERMINAL 4 AND 5 (PROX ELETR UNIT) AS PER WDM 32-61-04 PG 2, FOUND OK. REMOVED AND REPLACED PROXIMITY ELECTRONIC UNIT PER M/M 32-61-01-2.