Air Conditioning - AC blower cutting on and off

My AC was working a few days ago but today its not. The outside condenser seems to be fine although there is no hot air blowing out the top. The fan runs fine though without any observable effort on its part. The inside unit seems to be the issue. It cuts on and off without warning. The blower seems to become burdened and then just cuts out. The coldness of the air vents was so so. I cant say it was all that great so I probably do need to have a shot of freon but could that also be causing the inside blower to get wacky and cut out? Up till it quit my AC would pretty much run way longer then I suspect it should have. The unit is very old and takes a very long time to cool the house. I am seriously wondering if I shouldn't just replace the entire thing but cost is a factor. For less then 100 bucks I can probably have the coolant replaced/refilled and back up and running for another summer.

I usually pay about 300 to 400 a month in electricity bills. Last month it was only 160 and I didn't run the unit at all so that seems to be my basic household electricity usage. With the ac or heater going it easily doubles. If I bought a new unit would I be able to save enough from electric bill savings to make it worth the investment or would I only save a few bucks on my bill? Any ideas on why the AC keeps cutting off?

Update: I opened the unit in the house where the heater and blower are. At first the blower wouldn't come on at all even after the unit outside fan did come on. After some coaxing from the thermostat and playing with the settings I did get the blower to kick on. There was a lot of noise from 1 of the electrical box things attached to the wall of the heater. Switches, capacitors I don't know what those things are or what you call them but one of them was rattling quite a bit. It looks like some sort of relay switch. How could I test this thing and or replace it? There are two boxes in there that might be an issue. One of them has 2 wires and the other seems to have a few more. Maybe I should just replace them both huh?

You will probably need a technician to diagnose your problem. But, you may just have a bad blower relay or even a bad thermostat. To diagnose further you need to know if you have power to the motor when it's not running. If power is there, your motor is likely bad.

My AC was working a few days ago but today its not. The outside condenser seems to be fine although there is no hot air blowing out the top. The fan runs fine though without any observable effort on its part. The inside unit seems to be the issue. It cuts on and off without warning. The blower seems to become burdened and then just cuts out. The coldness of the air vents was so so. I cant say it was all that great so I probably do need to have a shot of freon but could that also be causing the inside blower to get wacky and cut out? Up till it quit my AC would pretty much run way longer then I suspect it should have. The unit is very old and takes a very long time to cool the house. I am seriously wondering if I shouldn't just replace the entire thing but cost is a factor. For less then 100 bucks I can probably have the coolant replaced/refilled and back up and running for another summer.

I usually pay about 300 to 400 a month in electricity bills. Last month it was only 160 and I didn't run the unit at all so that seems to be my basic household electricity usage. With the ac or heater going it easily doubles. If I bought a new unit would I be able to save enough from electric bill savings to make it worth the investment or would I only save a few bucks on my bill? Any ideas on why the AC keeps cutting off?

Update: I opened the unit in the house where the heater and blower are. At first the blower wouldn't come on at all even after the unit outside fan did come on. After some coaxing from the thermostat and playing with the settings I did get the blower to kick on. There was a lot of noise from 1 of the electrical box things attached to the wall of the heater. Switches, capacitors I don't know what those things are or what you call them but one of them was rattling quite a bit. It looks like some sort of relay switch. How could I test this thing and or replace it? There are two boxes in there that might be an issue. One of them has 2 wires and the other seems to have a few more. Maybe I should just replace them both huh?try replacing the motor capacitor first. it that doesn't work, the motor needs replaced. the fan relay on the board could be going bad also.