What would cause heat/ac blower motor on car to stop?

Every so often the heat/ac motor on my car stops. I remove it (which is fairly easy) and put it back on. Then it works fine. I have checked the connections and fuses. They seem fine. The switch works too. Could it be a faulty motor? A new one costs $25-$50. Any ideas?
2002 Ford CV, V8, with climate control.

When the brushes in the motor wear over time and use they get shorter, lose spring tension, and have carbon seizing them up. Pounding on the motor will start it working many times. You going to fool around over $50?!

It could be a faulty ground. If it quits again test the power to it with a multi-meter. If it is getting power and still won't run when you plug the plug back up then replace it unless you want to get into repair of the brushes and internal wiring.

Try replacing the the blower motor resister could be faltly.

Can you be more specific please?