Q: How to check and replace the Cooling Fan Assembly?
A: The PCM controls the radiator cooling motor circuit via the radiator fan relay, using the Engine Coolant Temperature Sensor to monitor engine heat. If overheating is detected, the PCM activates the radiator fan. The condenser cooling fan motor circuit is controlled by the condenser fan relay, linked to the AJC control relay circuit. To test fan motors, connect them directly to the battery using fused jumper wires. If the fan doesn't work, replace the motor. If the fan doesn't turn on when hot, the issue lies in the cooling fan motor circuit or PCM. If all components are functional, get the PCM checked by a dealer. Replacement steps depend on the vehicle model and year.