What was found
AFTER SELECTING LANDING GEAR UP, LEFT GEAR DOOR WOULD NOT CLOSE. ALSO HAD RED "UNLK" ON LEFT GEAR. GEAR EXTENDED NORMALLY. PER CREW DEBRIEF, POSITION SYS 1 WAS NEVER SELECTED. SYSTEM 2 WAS SELECTED THE WHOLE TIME. SYSTEM 2 HAS HISTORY. R/R LT MLG DOOR UPLOCK ASSEMBLY REF AMM 32-31-33-04 REQUIRED OPS CKS AND LEAK CKS GOOD, MLG DOOR UPLOCK P/N A25441001-2, S/N M736.