First check to see if the fuse is OK. If the pump impeller is shot or stuck, it may cause the motor to overload. (Also can you access the body of the motor and see if it is warm--any indication of current draw--such as lower voltage, if you don't have an amp meter in line with the electrical system.
The pumps have a slot in the back of the shaft--which is exposed on the back of the motor--often a stuck impeller can be turned, manually with a screw driver...problem is access to the pump....
The impeller is fairly easy to change, if you can get the entire unit out.