Q: How to diagnose and repair a non-functioning cooling fan in an overheating engine on Ford Fusion?
A: If the cooling fan is not functioning when the engine overheats, first inspect the fan relays in the underhood fuse/relay box and check all wiring and connections to the fan motor. If no obvious issues are found, it's advisable to diagnose the cooling fan system and circuit further. Disconnect the negative battery cable and the fan motor electrical connectors, then raise the vehicle and drain the cooling system, detaching the upper radiator hose. For 2012 and earlier models, on automatic transaxle-equipped vehicles, release the clips securing the transmission cooling lines to the fan shroud, disconnect the electrical connectors to the fan-control electronic module, and move the wire harness away from the shroud. Remove the shroud using appropriate clips and fasteners, and lift the fan/shroud assembly from the vehicle. For 2013 and later models, remove the transaxle cooling lines support bracket bolt, the air filter housing, and the air conditioning refrigerant line block mounting bolt. Remove the upper radiator support, the radiator upper mounts, and the fan shroud upper fasteners. Remove the radiator lower support panel, support the radiator assembly, and remove the fan shroud lower mounting bolt(s). In all models, detach the fan blade from the motor by removing the nut or retaining clip, and remove the fan blade from the motor. To detach the motor from the shroud, remove the retaining bolts. During installation, ensure the rubber air shields around the shroud are in place. Reconnect the battery, refill the cooling system, bleed the air, start the engine, and check for leaks and proper operation.