What was found
MKE - FLT 6350 - DURING APPROACH, MKE TO MKE TRAINING FLIGHT, CREW SELECTED LG DOWN, DID NOT EXTEND. WHEN CREW SELECTED LANDING GEAR DOWN, LG RELAY CB OPENED. CREW DECLARED EMERG, MANUALLY EXTENDED MLG, AND AFTER RECEIVING A 3-DOWN LOCKED IND, MADE SAFE LANDING. MAINT INSP ACFT AND REPLACED LG GROUND SERVICE VALVE. AFTER GROUND CYCLES, ACFT TEST FLOWN, LG FAILED TO EXTEND WITH LG RELAY CB OPENING. MAINT INSP ACFT AND REPLACED TB-150, SPLICED A WIRE AT RT GEAR UPLOCK SWITCH. AFTER GROUND CYCLES, ACFT TEST FLOWN, LG FAILED, CB OPENING. MAINT INSP, FND WIRE G11A22 CHAFING TO GROUND, LT WING CENTER SECT. WIRE REPAIRED, GEAR GROUND OPERATED, ACFT TEST FLOWN. TEST FLT SUCCESSFUL, ACFT RETURNED TO SERVICE.