What was found
JUST OUTSIDE THE FINAL APPROACH FIX WE PUT LANDING GEAR INTO THE DOWN POSITION AND RECEIVED THE GEAR DISAGREE RIGHT CAS MESSAGE. WE WENT AROUND AROUND, UTILIZED THE THE LANDING GEAR BLOW DOWN AS WELL AS THE LANDING GEAR HANDLE IN THE LAV PER THE QRH, GEAR DISAGREE RIGHT CAS MESSAGE REMAINED. REMOVED FAULTY RT WBA-MLG UPLOCK SWITCH, & REPLACED WITH CUSTOMER SUPPLIED NEW WBA-MLG UPLOCK SWITCH IAW MM 32-32-25.