I have a ceiling fan/light with wiring for controlling the light and the ceiling fan separately. I have two separate switches in the wall. I have installed two separate Lutron fan control switches with a slide to control the speed. Each time the switch works fine after being installed but begins to buzz or sound like it's shorting out internally in a few hours after being installed. This is with the fan switch off. The wall box has one black wire, that is hot, coming in and one black wire, that is not hot, going out to the fan. Am I just getting bad switches or is something else going on?

