DLookup would work and don't have to bother with the connection and recordset code. But if you really want to use SQL then you need a recordset and set box to the value of field in the query.
Code:
Dim conn As ADODB.Connection
Dim rs As ADODB.Recordset
Set conn = CurrentProject.Connection
Set rs = New ADODB.Recordset
rs.Open "SELECT CFS FROM loadDateCFS;", conn, adOpenStatic, adLockPessimistic
Me.txtCFS = rs!CFS
rs.Close
That's how I do it. This query will retrieve all records but the textbox is populating with value from the first record.
The real question is why do you need to do this, what are you really trying to accomplish? Can this field be a part of the form's RecordSource?