The cost to replace a run capacitor for a condenser fan motor from an HVAC contractor can range from $150 to $275 depending on the size and the labor need to install the part. 2) The Condenser fan relay is bad. New condensers have a relay they turn the motor on and off when the system starts and turns off.The cost to replace a condenser fan relay can range from $175 to $275 the cost depends more on the make and model of the unit and the contractor installing the part.3) The condenser fan motor electrical winding are bad (burnt motor).eplacing the motor without the same specs can cause higher utility cost and a shorter life span of the air conditioning system. Also replace the run capacitor when you replace the condenser fan motor. The average cost to replace the condenser fan more can range from $350 to $575.