Hi Mark
Quick test is put gnd to black wire and +12V to blue wire, the motor should run at lower speed, remove from blue and put power to grey wire and should run at fast speed.
Next remove power to grey and put power to blue/black, this may move motor at slower speed momentarily until it stops or may not move. apply power to blue momentarily to get motor running and remove, leaving power on blue/black, the motor should keep running until it reaches the stop/park position. if all that works, then the motor is ok.
Peter