Conditional Formatting code not working

Hello All

Ive put this coding together that sits the individual sheet code:

Private Sub EOBTcondition()

Dim Rng As range
Dim texttime As range

If Rng Is Nothing Then
Else
End If
Exit Sub

Set Rng = range("b2:b200")
Set texttime = Sheet1("b9")
For Each cell In Rng
Select Case cell.Value
Case Rng - textime <= 200
    cell.Interior.ColorIndex = 6
End Select
Next

End Sub

...and it doesnt work.

What it's supposed to do is take the value in cell b9 of Sheet 1 which is in a reference table, and ask whether or not the difference between its value and the value in any one of the cells in Rng is equal to or less than 200. If its within 200, the cells in Rng that are within 200, highlight yellow.

Am I barking up entirely the wrong tree, or am I close?
Any ideas?

thanks!
Adam