Command Buttons and Auto-Filter

Hey All-

I was trying to alter a command button to auto-filter based on input from
the user in cell C1. (Which is actually a merged cell of four other cells)

The data range is A4:BJ3500 and this is what I'm using but it returns no
results even if I put in a number that I'm certain is in column "A" - field
1.

Any ideas greatly appreciated!

Private Sub CommandButton1_Click()
Range("A4:BJ3500").Select
Selection.AutoFilter Field:=1, Criteria1:="=*" & Range("C1").Value _
& "*"
End Sub