Overload protector is kind of a fuse for the motor. In case if the motor overheated due to overload, it shits of the motor. It is a part of the motor. You can see it on the following picture as a piece on the right side with the pink and orange wires. Check it for continuity. If it's open, the whole motor has to be replaced.



Besides the thermal fuse which you already tested, check for continuity two other thermostats on the heating element housing.

Gene.