OK. Pulled cowl off, filters still in place prior to pulling off, reached in and found no debris, squirrel cage spinning freely. Fuse good. Now more to add.

With plug attached to switch and using light probe have discovered the following..... With switch off I have power to one wire. With switch in any position I have power at all leads no matter what speed position I have blower switch set at.

I tested with switch plugged in and back of plug removed. I am definitely not an electricial genius and am still stumped. Where to next?