This motor only runs for the first minute or two on start up, and at which point it shuts off along with closing the diverting valve. So have you confirmed voltage at motor by back probing the motor leads, and then turning on the truck?
With the air line disconnected from the pump. On start up the diverting valve should open and you should hear a farting sound as exhaust escapes. after a few minutes the diverting valve should close and the farting sound should go away if the valves are working properly.
At least this is how it worked on my old Taurus.