A/C Intermittent Operation Due to Cooling Fan/FCM Failure

To confirm a failure in the cooling fan or Fan Control Module (FCM), set the A/C to 'LO' while the engine is at idle. Both radiator cooling fans must engage immediately. If the fans fail to start or only operate at high speeds, the FCM or fan motor is likely failing to shed heat from the condenser. Use a multimeter to check for voltage output from the FCM to the fan motors; if the FCM receives an 'ON' signal from the ECU but fails to output power to the fans, the FCM or fan wiring is the root cause.