Troubleshooting Common Problems with an Air Conditioner Condenser

A man works on an AC unit.

Diagnose problems with an air conditioner condenser by following the following steps if yours is faulty. Before troubleshooting, however, make sure that all components in the appliance are clean and free from dust, debris, and particles as these easily slow down its operation.

Outdoor Condensing Fan Motor

If a motor run capacitor is faulty or damaged, the outdoor condensing fan motor may stop running as it is required. Check the motor run capacitor, test if it is working. Replace it with a new capacitor if it is damaged or faulty.

If it is in good condition, then check out the motor. Find out if the fan blade is tight or stiff. This might cause it not to run properly. If the fan blade does not turn, replace the motor with a new one.


Start troubleshooting the air conditioner by checking the thermostat. It should be on cool and always set lower than the room temperature. Incorrect settings on the thermostat easily make the device not regulate temperature as needed. If the thermostat is set correctly but does not work, replace it with a new one.

Furnace or Air Handler Fan

If the fan is not running, then the problem can be attributed to faulty breakers. Make sure that the breakers for the furnace or air handler and the air conditioner are on. Shut the breakers off and set them on, check if the fans run.

If this does not correct the problem check the thermostat. If the thermostat is in good condition, check the furnace or air handler control board. If this is in good condition, check the wires between the furnace or air handler control and the thermostat are properly fixed.

Faulty Blower

If a blower is not running it can be as a result of a faulty blower motor, run capacitor, or the air handler control board. Start by checking for ice particles around the blower unit. This can interfere with its operations. Let the ice melt by shutting down the outside unit for a few hours while leaving on the blower to run.

Run a capacitor test to check if it is working correctly. This can be done if there is no presence of ice particles around the unit. If it is in good condition, inspect the wires around the unit.

Check that all pieces are securely fixed to the unit, inspect for damages or cuts, and repair them as necessary.

Air Conditioning Outdoor Condensing Unit

This is also known as the heat pump unit. If it does not shut off, turn off the breaker or pull the outdoor disconnect. Check if the contractors are in good condition. If they fail or become faulty, the outdoor condensing unit will not come on at all.

Look out for dirt, debris, or insects between contact points. Clear away dirt and debris. Turn on the unit and check how it works. If there is still a problem, replace the contactors with new ones.