Onlydarksets

The Logitech Harmony remote software does not have a native way to support Vizio’s input switching.  Vizio has a dedicated button for each type of input, which is different than the 4 methods offered by Harmony.

To get around it, choose an input that you don’t use (e.g., RGB), and use that as the input for every Activity.  Then, from the main screen for the Activities:

1. Click Customize for the particular Activity
2. Click “Next” until you see the option for “Yes, but I want to add more control of options and devices for this Activity.“  Select that option and click “Next”.
3. Click Save
   
4. Click Next
5. Click “Add Action”.
6. Select “Send this infrared Command” and select the input switch command.  Then click Next.
   
7. If you need to get to the second of the inputs (e.g., HDMI 2), add another Action with the same command.

You have to do this for each Activity, but it seems to work pretty well.