Set your test meter to the lowest OHMS scale. Verify that the brake is engaged. Insert the test leads into the top two terminals in the plug. You should be reading the resistance of the brake. It will be between 50 and 85 Ohms.
Insert the test leads into the bottom terminals. You will be reading the armature resistance, which is very low, between .8 and 5 Ohms.If you get no reading at all, or a direct short (0 ohms) in either location then it is defective and the motor/brake must be replaced.