740 blower motor oddity

I've known that the blower motor in my 89 745 doesn't work at all- no sound whatsoever.
Today, I noticed that when the switch is turned all the way to "4", there is a click from the region of the motor. It clicks on 4 and only 4 no matter what flapper or temp position is selected.

So what needs to be replaced? The resistor or the motor?

Just pop the blower motor out and look at it. Mine clicked occasionally like yours and would blow fuses. The blower motor was almost seized, it barely spun. Removing it should only take you about ten minutes.

Apply 12v power and ground to the fat wires at the blower and see if it goes.