Hello james gray. Your description is for a hand control type motor with the control knob on the handle. Disconnect the power to the motor. Carefully disassemble the handel making note of procedures. Check your wiring to control. It would be helpful to use a multimeter to check the voltage on the wiring connections. This should confirm the wiring shorting or most likely a bad switch. The switch could be found from a local electrical supply store or a marine store.