What was found
DURING APPROACH TO LANDING, GEAR WAS EXT AND INITIALLY INDICATED 4 GREEN/SAFE. AFTER APPX. 1 MIN GEAR INDICATION ON LEFT GEAR TURNED RED AND ON SYNOPTIC FLASHED BETWEEN GREEN AND RED. AFTER APPX. 10 MIN LEFT GEAR INDICATED SOLID GREEN ON SYNOPTIC. CREW FOLLOWED QRH FOR GEAR HANDLE DOWN WITH UNSAFE INDICATIONS. CREW DECLARED EMERGENCY. AFTER LANDING, SYNOPTIC STILL FLASHED BETWEEN RED AND GREEN. CREW DECIDED TO HAVE MX PIN GEAR. FOUND LH MLG PROX SENSOR SUPPORT BRACKET BROKEN, REPLACED WITH NEW IN REFERENCE TO AMM 20-50-02-2. ALSO CHANGED THE PROX SENSOR FOR UP AND LOCK ON THE LT MAIN LANDING GEAR AMM 32-61-15-4. COMPLIED WITH ALL REQUIRED OPS CHECKS AND ALL INDICATIONS NORMAL. ACFT GOOD FOR SERVICE.