The blower on my central air unit is not working. It starts to hum and if I spin the blades (which spin freely) manually it turns on for a few minutes but then shuts off. I turned the thermostat to ON and cool. Not sure the model number all I know is it says Sears All Conditioner on the side of unit. Any help would be greatly appreciated.

Sounds to me like one of the widnings has gone bad or your capacitor needs replaced.

How would I know if it was one or the other??

If you have a multimeter that can read microfared you can check the capacitor. If it is weak it will need replaced.

You can try changing the fan speed and see if another winding works. If you can read a wire diagram it will show you what speed is high medium and low and where to place them on board to change speeds.

If you could find the model and seriel number it would help. Now adays sears units arer made by carrier corp and might be able to find a wireing diagram.

How old is the unit by the way?

The Wiring Diagram is on the door of the unit, so I was able to try the other speeds and I was still having the same problem. My multimeter does not measure microfarad So I am not sure about the capacitor. I can not find anything on the model or serial number on the whole unit all it says is Sears All Conditioner...

Usually if the motor start by hand and stays running, it's a bad cap. However in your case the motor starts only for a short period. I would still get the cap checked, or even replace it(they are cheap), but I'm betting your motor is in need of replacement.

Thanks everybody for your help I changed the capacitor and the blower is running great again. Thanks again!

Glad that fixed it.