Text color detect from Conditional Formatting?

Special thanks to Brian Hessey (Modified his code)

Sub ColourCell()
On Error Resume Next
Dim c As Range
For Each c In Selection
    If c.Font.ColorIndex = 3 Then
        c.Interior.ColorIndex = 40
        End If
    Next c
End Sub

How can this code detect text color that is set with "Conditional Formatting", it seems Conditional Formatting can set text color with out an actual value to compare to!?
It works fine on cells with manually set text color.