How to Fix an Air Conditioner That Does Not Work

Move the thermostat setting to "Cool," if necessary. Adjust the thermostat temperature to below the current indoor temperature.

Examine the air conditioner's cord to make sure it isn't burned. Replace a damaged or faulty cord. Plug the air conditioner cord into the electrical outlet, and turn the air conditioner on.

Turn the power switch of the furnace to the "On" position if you have a central heating and cooling unit. Go outside and flip the outside power switch to "On." The switch is normally located in a box mounted against an exterior wall near the condenser unit.

Unplug the air conditioner cord from the outlet. Plug in a lamp or another device to see if there is power to the outlet.

Examine the fuse or circuit breaker that corresponds to the air conditioning unit. It's located inside the fuse box or the circuit breaker panel. Replace the fuse if blown. Push a tripped circuit breaker completely to the "Off" position and then completely over to the "On" position to reset it.

Unplug the air conditioner's power cord. Pull off the air conditioner's front grill and control panel.

Locate the selector switch, which allows you to choose the fan speed, behind the control panel. Look for any signs of burn marks on the switch terminals.

Loosen the selector switch screws, using a screwdriver, and remove the switch. Install a new switch of the same type, tightening it into place with a screwdriver.

Install the control panel and front grill onto the air conditioner. Plug in the power cord, and turn on the air conditioner on to see if it works.