Make your measurement across the two hot wires, looking for 240 volts. Measuring one wire at a time to ground will not show a problem if you have one leg open. The open leg side will still show 120 volts to ground since current can flow from the good leg, through the motor (or the control transformer in the switch), to your meter. If I was a betting man, I'd bet one leg of your 240 is open.
An alternate way to test would be to connect some other 240 volt load (if you have one) to the same circuit, or connect your motor to a different 240 volt circuit.
--I had my patience tested. I'm negative--