If your air conditioner is not moving air, you could have a broken air conditioner fan. This is not as hard to replace as it sounds. The most important part is getting the correct replacement part. You will need to test the unit, so it is much easier if you have an assistant.
Step 1 - Get the Correct Replacement Fan
You will need to use the model and serial number along with the manufacturer to obtain the correct fan. You usually will have to go through an authorized dealer, but sometimes they can be crossed over to a generic type that fits these units.
Step 2 - Remove the Old Fan
Turn off the main breaker that is for the air conditioner unit. If your unit is on the roof, you will need to find a safe place to climb up to it. If it is on the ground just locate the grate over the fan. Remove all the screws holding the grate or panel over the fan. Put the screws in a baggie or someplace you won't drop or misplace them. Locate the house fan. Sometimes the fan is attached to the grate so it is easier to remove. If that is the case, simply disconnect the wires and remove the fan from the grate housing. If it is not attached, you need to locate the housing screws in the back of the fan holding it in place and remove them. Then disconnect the wires that are attached to the fan. Set the old fan aside.
Step 3 - Install the New Fan
Take the new fan and hold it up next to the old one making sure it has the same connections and attachments. If all is well, then first attach the new wiring to the fan. Using the old screws you removed, reinstall the fan and tighten all the screws holding the fan in place. Replace the grating over the fan. Make sure you tighten all the screws down tight. Now you are ready to test the fan.
Step 4 - Test the Unit
Turn the breaker for the air conditioner back on. Make sure you close the door on the breaker panel. Turn the air conditioner down to a level where it should turn on. Watch the unit to make sure the fan is running. There should not be any tinging noises; if there are you have the fan wrong or the grate is bent and the fan is hitting it. Otherwise, you have done a good job; enjoy your cool air.