The run capacitor on an air conditioning unit is a metal cylinder or oval-shaped can that provides a boost of electrical power to the fan motor and compressor. Usually, air conditioners have a dual capacitor that has three terminals on the top, a common, a fan and a hermetic. Wires from the unit are connected to this by female spade wire ends. If you need to install a new capacitor, you can do so in a matter of a few minutes.
Things You'll Need
Needle nose pliers
Turn off power to the outdoor unit via the electrical disconnect or breaker.
Remove the electrical panel cover of the air conditioner by taking out the screws that hold it to the unit. Verify that the power is off with your electrical meter by setting your meter to measure voltage and touching the probe ends to the lead side on the contactor. This is where the wires enter the unit. You should read no voltage.
Use a screwdriver to ground the terminals of the capacitor to the metal cabinet of the air conditioner. This will discharge any stored charge within the capacitor. Write down the colors of the wire, where they come from and which terminal on the capacitor they connect to. You can also check the current wiring against the wiring diagram located on the inside of the panel cover.
Remove the mounting screw holding the capacitor in place. Use your pliers to pull off the wires. Read the rating label of the capacitor and replace it with one of the same voltage and microfarad rating. For example: 35/5 mfd. @ 370 volts.
Mount the new capacitor in place of the old and secure with the mounting screw. Reconnect the wires according to how they were mounted on the old capacitor.
Replace the electrical panel cover and secure with the same screws you previously removed. Reconnect power to the unit.
Only professional electricians or those experienced with working with electricity should attempt to service an air conditioner.