How to Troubleshoot Air Conditioning Unit Problems

Inspect the power cord to the unit for damage. Check the wall outlet to ensure it is working. Plug another appliance that you know is working properly into the plug. If it operates, then the problem is with your A/C unit.

Ensure that the dials on the front of the unit are seated properly and aren't damaged or functioning improperly.

Push the reset button on the power cord if it has one and try turning on the unit. The current interrupter may have tripped.

Check the circuit breaker for the unit. This should be located in your whole-house circuit breaker box. If the breaker continually trips when you run the unit, hire an electrician to upgrade or replace it.

Listen to the unit when it is powered up to see if the blower fan is operating. You should hear it running when the unit is turned on. If not, this may also require service from a certified A/C technician.

Open the front of the unit, according to the manufacturer's directions. Remove a few screws with a Phillips screwdriver first. Clean the air filter if it looks dirty. Refer to your user's manual for details on the location and removal of your specific unit's filter. Remove the filter and rinse it with soapy, warm water until the water running through the filter is clear.

Clean the aluminum fins that provide cooling with a very soft brush. Remove dirt in the direction of the fin (up and down, rather than side to side). Carefully suction out any remaining debris with a vacuum cleaner. The fins are made of soft aluminum so take care not to damage them when cleaning.