Populating combobox dependent on another combobox

Hi everyone...I trying to develope a userform in Excel 2010, that has 3 comboboxes dependent on each other. What I am having trouble with is populating the 3rd combobox with the data from the spreadsheet worksheet "Chassis Specs" column "B" which is dependent on column "A" which is the result of combobox 2.

Here's what I have for the code for the 2nd combobox that should populate the 3rd combobox:

Private Sub ComboBoxChassisSubType_Change()

Dim CRange As Range, c As Long, v

With Sheets("Chassis Specs")
c = Application.Match(ComboBoxChassisType.Value, .Range("A2:A19"), 0) + 1
v = Worksheets("Chassis Specs").Range("A2:A19").End(xlToRight).Column
If IsArray(v) Then
ComboBoxChassisSpec.List = v
Else
ComboBoxChassisSpec.AddItem v
End If
End With

If Not ComboBoxChassisType = "" Then
ComboBoxChassisSpec.Enabled = True: ComboBoxChassisSpec.BackColor = &HFFFF&
End If

End Sub