The 4051 control pins should not be allowed to "float" or unexpected things will happen. You may need to have a high value resistor between the control pin and ground to make sure that the control pin is low when it is not being made high.
The 4051 control pins should not be allowed to "float" or unexpected things will happen. You may need to have a high value resistor between the control pin and ground to make sure that the control pin is low when it is not being made high.