Turn the circuit breaker on the air conditioner to "Off."
Verify that the air conditioner has no alternating current (AC) voltage with your volt/ohm meter.
Set your volt/ohm meter to the ohms scale.
Do one of the following:
If your volt/ohm meter has a continuity test built in, dial the rotary switch to the continuity test setting.
If your volt/ohm meter does not have a continuity test built in, dial the rotary switch to the ohms setting.
Touch the two leads from the volt/ohm meter to the white wire and each of the other wires. A lack of continuity between the white wire and any of the other wires indicates an open circuit and requires that you change the motor.
Using the appropriate continuity check for your volt/ohm meter, touch the two leads from the volt/ohm meter to each wire and the green/yellow wire. If you get continuity, you have a grounded motor and it must be replaced.
Remove the screws around the outside of the plastic housing that covers the air conditioner.
Lift off the plastic housing and set it out of the way.
Take the screws off of the evaporator to access the squirrel cage.
Remove any sheet metal, such as duct work, that is in your way.
Take the cover off of the electrical access box so that you will be ready to disconnect the wires to the fan motor.
Remove the screws that secure the motor and the squirrel cage fan to the assembly.
Remove the squirrel cage fan from the motor shaft. On some units, you will see Allen screws that secure the fan to the shaft. You will need to use a long T-handle Allen wrench to loosen the Allen screws. If the unit has been in service for a number of years, the fan have rusted to the motor shaft. In that case, apply a liberal amount of penetrating oil to loosen the fan.
Slide the fan onto the new motor shaft making sure that the flat spot on the motor shaft aligns with the Allen set screw on the squirrel cage fan.
Tighten the Allen screw to secure the squirrel cage fan to the new motor shaft.
Reinstall the fan assembly into the air conditioner.
Replace the mounting screws.
Reroute the motor wires to the electrical access box.
Re-connect all of the wires.
Ensure that the blades of the squirrel cage fan are free and centered so that they will not to rub on the evaporator housing.
Reinstall the evaporator and evaporator housing.
Reinstall the air conditioner's plastic housing.
Turn the power on at the circuit breaker.
