Are you building with the Switchboard wizard? Don't like and never used it. It uses macros. I don't use macros. Generally avoid the wizards.

You show a function but not showing code behind the buttons, which is probably macros that call the function. If you want to use a function then make it a function with an argument.

Function OpenExcelFromAccess(strFileName As String)
Dim xlx As New Excel.Application
Dim xlw As Workbook
Dim xls As Worksheet
Set xlx = CreateObject("Excel.Application")
Set xlw = xlx.Workbooks.Open strFileName
set xls = xlw.Worksheets(1)
xlx.Visible = True
'do something with xls
End Function

Then call the function from button and pass file name:

OpenExcelFromAccess("Conduit Fill and Voltage Calculator")