What was found
LEFT MLG LANDING GEAR RETRACTION: SFO AIRPORT LEFT MAIN GEAR RETRACTION GOT EICAS: GEAR DISAGREE L. ALSO YELLOW "DN" GEAR INDICATION LEFT MAIN. RAN QRH AND GOT GOOD 3 GREEN. LANDED NORMALLY. RETRIEVED PARTS FROM FBO. ACCOMPLISHED INCOMING PART CHECK, PART CHECK GOOD. ARRIVED AT AC. PREPPED AC AND JACKED AC AS REQUIRED. REMOVED WBA-MLG UPLOCK SWITCH DUE TO INTERNAL FAILURE. INSTALLED NEW WBA-MLG UPLOCK SWITCH AS REQUIRED. PERFORMED AND FOUND OPERATIONAL TEST SATISFACTORY. DOWN JACKED AC AS REQUIRED. ITEM NO LONGER STANDS. WORK DONE IAW AMM 32-30-15 & 32-32-25.