Excrating Last 3 Letters From Cell Text

Greetings,
I am not able to figure out what I am doing wrong. I need to determine if the last 3 letters for cell AI4 = "AUV". However my code is not recognizing this.

Sub conAUV_pHs1()
    Dim ws As Worksheet
    Dim b4Var As Variant
    Dim ai4Var As String
    Set ws = ActiveWorkbook.ActiveSheet
    b4Var = "Rest #"
    ai4Var = "AUV"  'This cell's last 3 letters will always be AUV.
If ws.Range("B4").Value <> b4Var Or ws.Range(Right("AI4", 3)).Value <> ai4Var Then
    uf_Message_conAUV_phase.StartUpPosition = 2
    uf_Message_conAUV_phase.Show
    ActiveWorkbook.Close False
    End
    Else
    End If
End Sub