Code to return the 2nd highest value from each tab of another workbook to current workbook

Hello! I'm extremely new to macros and codes and have only run a few successfully. I apologize for any glaring mistakes!

I'm trying to come up with a code to return the 2nd highest value from the "D" column of each tab of another workbook to my current workbook. Please see my code below. I pieced it together from other codes that I've used in the past and another code that I found online. I keep getting errors left and right when I try to alter the code. When I try to use the one below, I get a "Compile Error: Type Mismatch" popup. Can anyone help me fix this code/come up with a better one? Thank you!

Sub Test()

  Dim WS As Worksheet
  Dim Source As Range, Dest As Range, rng As Range, cell As Range
  Dim highestValue As Double, secondHighestValue As Double
  
  Set rng = "D:D"
  highestValue = 0
  secondHighestValue = 0

  'Set the first cell
  Set Dest = ThisWorkbook.ActiveSheet.Range("D3")
 
  'Visit each sheet
  For Each WS In Workbooks("CAMPUS SHUTTLE TRACKING 2010-2011.xls").Worksheets
  'Find Highest Value
  For Each cell In rng
  
  Next cell
  
  If cell.Value > highestValue Then highestValue = cell.Value
  
  'Find Second Highest Value
  
   For Each cell In rng
  
  Next cell
  
  If cell.Value > secondHighestValue And cell.Value < highestValue Then secondHighestValue = cell.Value
  
    'Write the value into there
    Dest = cell.Value
    'Refer to the next cell below
    Set Dest = Dest.Offset(1)
  Next
End Sub