1. An ohmmeter check for continuity between the motor connector terminals. In the OFF conductivity should be between 4 and 5, in the LOW position - between the terminals 5 and 6 and in position HIGH - between terminals 3 and 6.
2. If conductivity is absent, replace the motor.
3. Check the engine speed when submitting additional wires to the battery voltage at the terminals of the motor connector. Connect the battery negative terminal to terminal 6 of the connector. When connecting the positive battery terminal to terminal 5 engine to run at low speed, and when connected to terminal 3 of the motor must rotate at a high speed.