Turn off the unit. Remove the protective grill that holds the condenser coils in place with a Phillips head screwdriver. Set it on the ground and clean off the fins of the condenser with a soft brush. Scrub gently to remove any debris.
Vacuum the fins with a vacuum brush attachment. Attach the grill back over the evaporator coils and secure it in place with a screwdriver.
Turn off the thermostat. Reset the power and set the thermostat to turn on the air conditioner. Wait five minutes and then turn it back on and allow it to run for a few minutes. Check the two pipes that connect the condenser to the air handler. If one is warm and the other cool, your unit is working properly.
Turn off the unit again if it still does not work. Remove the grill again. Cover the motor on the inside so it does not get wet. Tape it with plastic sheeting and duct tape or cover it with a garbage bag. Clean the condenser coil on the outside of the air conditioning unit with a garden hose. Spray the entire area with the hose to remove any dirt and debris that may be causing the condenser to malfunction.
Move back and forth about 6 inches from the condenser coils until the entire are has been sprayed. Wait until the unit is dry before turning it back on to check whether it is now working properly. If the problem persists, then the condenser is out and will need to be replaced.