How long have you had the motor if they are dormant for any length time or bounced around on a mail truck the switch on the inside can get corroded or moved and not function.
When the switch plate is installed on the motor it needs to be clocked which requires the internals to be in a designated...
If you buy the 2 speed and use the 3sp switch it will not park and it will only have 1 speed.
I can restore your motor contact me if you would like
ns1aar.com