My Air Conditioner Blows Air, But It Isn't Cold. The Fan At The Furnace Appears To Be Running, But The Compreessor(?) (the Thing Outside) Isn't Running. What Can I Do To Repair It?

The principle used in air conditioning devices is similar to that in refrigerators. If your air conditioner blows air, but you can’t feel a difference in temperature, and the compressor isn’t working, it’s probably because your compressor has lost its cooling capacity. To solve this problem, you need to do one of the following: Check if the A/C switches work, if the ducts and air handler are in good order, and if the system controls are set and operate correctly. If all the above seem right, but you still can’t see the problem, you should seek for professional advice.

More often than not, air conditioning system problems are easy to diagnose and don’t involve a lot of money. However, due to the various costs which may occur, your technician will most likely look for small things first, to make sure he’ll keep your repairing costs to the minimum.

If your compressor doesn’t operate, this may be serious. Air passes through your air conditioning system; inside, there’s high pressurized refrigerant gas that, once sent through the condensing coils, returns to a liquid state. During this process, it cools down the environmental air, which is then sent inside the room. So, if your compressor doesn’t work, it’s impossible for you to feel any cold air coming from the unit.

Here’s a list of possible causes, sorted by importance and, implicitly, costs:

- The compressor motor is dead. In most cases, this implies changing the entire unit.
- The compressor experiences a series of electrical problems which can be fixed without actually changing the motor. This is preferable to the first situation, but it takes time to solve it.
- Various peripheral issues related to A/C adapters, cables and switches, current draws, conditions of filters, etc.

Except for the situation when you really know what you’re doing, you should seek help from specialized technicians.
 

It sounds like your fan motor has burnt out. This sometimes happens because the contacts that kick the fan motor off, become worn and do not release, which in turn, causes the motor to run continuously without shutting off. The end result is that it cooks the fan motor.
We just had to replace ours because of the same symptoms you are describing.
If you or someone you know, is mechanically inclined, you can shut the breaker off to the A/C unit, remove the cage that covers the fan, then take the fan and blower moter off.
The fan is connected to the motor. 
Once you remove the fan, you will see the motor. Remove the motor. Write down the name and model number of your air conditioner, then take the fan motor with you to an appliance supply store.
They will sell you a replacement motor. I would go ahead and pick up a new contact as well. It's not that difficult to replace.
Just make sure that when you disconnect the blower motor, that you make yourself a little diagram on where each color wire is hooked up before you disconnect them.
The shaft on some replacement motors may be longer than your original one. If it is a little longer, that's no problem. If it is quite a bit longer, you will most likely need cut it down to size. Also not a bid deal, but you will have to have a saw blade that is made to cut metal.
I know it sounds a bit difficult, but you are looking at around $140.00 to do the repair yourself, verses several hundred to call a repairman.
Most A/C repairmen charge a minimum of $70. To $100.00 just to come out and look at your A/C unit. Then, there's the chance that you may not get an honest one, who might try to tell you that you are going to have to replace the whole unit. Which could cost you upwards of two grand, depending on the size of your unit.

How old is the unit? It could be that it needs some cleaning, or the motor is going out in it. I think you might want to unplug it and clean it first, then if that doesn't work, then I would call in the repairman. Hope this helps.

If nothing is running in the outside unit (no fan, no compressor), then it is possible that the contactor switch in the outside unit is not getting a control voltage from your thermostat. This voltage comes from a small transformer mounted in the house, usually near the inside (evaporator coil) unit. This transformer could be bad, or you may have a bad thermostat (unlikely if the central heat works and is on the same thermostat), or the contactor switch itself (in the outside unit) may be bad. I have run across both these problems in the past, on different units. Got any friends that can check voltages with a test meter? Good luck.

Good grief people...the first thing to do is check the cotton-pickin' BREAKER box. If the breaker for the condensing unit(compressor) is thrown, re-set it and go from there. It could be "iced up". If that's the case, you might want to turn the cooling part off at the thermostat, and leave the fan on continuously until the unit thaws out. If it freezes up again, call a pro.

In this case, you can't repair it by yourself. You need to consult some expert to repair your air conditioner.