Search for subform record based on text box

@Ken Sheridan
Sorry for so many responses here.. I was able to fix the issue of not adding new records with each search. I noticed that the second subform on the parent form autofills, but with one Header SN (text box field on subform 1), there will be many records in subform 2. How do I make the subform 2 not fill? I was planning to have a search button on that subform as well to be able to search by a serial number there.

I have edited my code a bit (see below). I changed the text box to not have an equation that equaled the bound box for a SN, as I think this was making it so every time I clicked the search button a new record was added to the subform table. I have also made it so the bookmark action (from your on current event) is within the button click event (text box and button on subform), but I still cannot get the subform fields to fill. The parent form fills just fine. What am I doing wrong?

Private Sub Search_SN_Button_Click()  
    Const MESSAGETEXT = "No matching records found."  
     Dim ctrl As Control  
     Dim strFilter As String  
     Dim rs As DAO.Recordset  
          
     Set ctrl = Me.[Header SN Placeholder]  
        'Header SN Placeholder is not bound to the table, formula equals text entered in Header SN Field textbox on subform  
     strFilter = "[Furnace Run ID] IN(SELECT [Furnace Run ID] " & _  
         "FROM [Header Data] WHERE [Header SN] = """ & ctrl & """)"  
          
     If Nz(ctrl, 0) = 0 Then  
         ' turn off filter  
         Me.Parent.FilterOn = False  
         Me.Parent.[Header Data Form].Form.FilterOn = False  
     Else  
         If Not IsNull(DLookup("[Header SN]", "[Header Data]", "[Header SN] = '" & ctrl & "'")) Then  
             ' filter form to name selected in text box  
             Me.Parent.Filter = strFilter  
             Me.Parent.FilterOn = True  
               
             ' filter subform to selected Header SN  
               'Me.[Parent].[Header Data Form].[Form].Filter = "[Header SN] = '" & ctrl & "'"  
               'Me.[Parent].[Header Data Form].[Form].FilterOn = True  
               Else  
                 If Not IsNull(Me.[Header SN Placeholder]) Then  
                    With Me.[Header Data Form].Form  
                        .RecordsetClone.FindFirst "[Header SN] = " & Me.[Header SN Placeholder]  
                        If Not .RecordsetClone.NoMatch Then  
                            .Bookmark = .RecordsetClone.Bookmark  
                        End If  
                    End With  
                End If  
            End If  
        End If  
    If IsNull(DLookup("[Header SN]", "[Header Data]", "[Header SN] = '" & ctrl & "'")) Then  
             ' inform user if no matching records found  
             MsgBox "Sorry, no such record '" & [Header SN Placeholder] & "' was found.", _  
             vbOKOnly + vbInformation  
           
     End If  
  
End Sub  

Thank you for all the help! A few follow up questions...

The name of the subform control is Header Data Form, why do I get the error in my previous question (when bound text and button are on the subform) ?

I have changed the code for the button on my subform to match your findrecord example but use Me.Parent (see below), but I still get the same issue when I had the text box and button on the main form - it updates the parent form to the record that matches that in the text box, but the subform remains blank. Is the current event procedure what would update the sub form? Does the current event procedure and the after update procedure need to be separate? Can the bookmark action be in the after update (in my case, button click) procedure (as seen in the text before the End With statement)?

Private Sub Search_SN_Button_Click()  
    Const MESSAGETEXT = "No matching records found."  
     Dim ctrl As Control  
     Dim strFilter As String  
          
     Set ctrl = Me.[Header SN Placeholder]  
        'Header SN Placeholder is not bound to the table, formula equals text entered in Header SN Field textbox on subform  
     strFilter = "[Furnace Run ID] IN(SELECT [Furnace Run ID] " & _  
         "FROM [Header Data] WHERE [Header SN] = """ & ctrl & """)"  
          
     If Nz(ctrl, 0) = 0 Then  
         ' turn off filter  
         Me.Parent.FilterOn = False  
         Me.Parent.[Header Data Form].Form.FilterOn = False  
     Else  
         If Not IsNull(DLookup("[Header SN]", "[Header Data]", "[Header SN] = '" & ctrl & "'")) Then  
             ' filter form to name selected in text box  
             Me.Parent.Filter = strFilter  
             Me.Parent.FilterOn = True  
                  
             ' filter subform to selected Header SN  
             With Me.Parent.[Header Data Form].[Form]  
               .Filter = "[Header SN] = '" & ctrl & "'"  
               .FilterOn = True  
               '.RecordsetClone.FindFirst "[Header SN] = " & Me.[HeaderSN]  
               'If Not .RecordsetClone.NoMatch Then  
               '.Bookmark = .RecordsetClone.Bookmark  
              ' End If  
               End With  
         Else  
             ' inform user if no matching records found and show all records  
             MsgBox MESSAGETEXT, vbInformation, "Warning"  
             Me.FilterOn = False  
             Me.Requery  
             Me.[Header Data Form].Form.FilterOn = False  
         End If  
     End If  
  
End Sub  

I have also noticed that clicking the search button adds a new record to the subform table with just the parent form data and the entered SN, which I do not want. The control on the subform is now a palceholder, which is autofilled when the bound text box is filled. Why is this happening?

At the end, since I have a single form, I do not need it to show all records. Can I just change the lines between the last Else and End If to be:
'MsgBox "Sorry, no such record '" & [Header SN Field] & "' was found.", _
vbOKOnly + vbInformation

@Ken Sheridan I have attached a few screenshots of my setup. I believe the name of the subform control is Header Data Form, as well as the name of the source object.

Would the bookmark example be included in the first examples that you sent? Or do the first 2 examples need to be changed to be used for a button/text box on the subform? I am a bit confused where each example should be used

@Ken Sheridan

I tried this in my previous code when I was using the Findfirst instead of filtering. I get the error stating that Access can't find the field '1' referred to in your expression and highlighting line Set rs = Me.[Header Data Form.Form.RecordsetClone

Private Sub Search_SN_Button_Click()
If ([Header SN Field] & vbNullString) = vbNullString Then Exit Sub
Dim strCriteria As String
Dim rs As DAO.Recordset

strCriteria = Me![Header SN]  
  
Debug.Print "Criteria:", strCriteria  
  
Set rs = Me.[Header Data Form].Form.RecordsetClone  
Dim i As Long  

For i = 0 To rs.Fields.Count - 1  
    Debug.Print rs.Fields(i).Name,  
Next  
rs.MoveFirst  
Do Until rs.EOF  
    Debug.Print  
    For i = 0 To rs.Fields.Count - 1  
        Debug.Print rs.Fields(i).Value,  
    Next  
    rs.MoveNext  
Loop  
  
rs.FindFirst "[Header SN] = '" & strCriteria & "'"  

If rs.NoMatch Then
MsgBox "Sorry, no such record '" & [Header SN Field] & "' was found.", _
vbOKOnly + vbInformation
Else
Me.Bookmark = rs.Bookmark
End If
rs.Close
txtGoTo = Null

End Sub

@Ken Sheridan

The current code I have (button and text box on parent form), based on the second example in your first response, does not fill in any fields in the subform, just the parent form (code in my last response). What am I missing? My ultimate goal is for this button/text box to be on the subform (questions on this below), but it might take me a bit longer to figure out so I am ok with it being on the main form if I can get it to fill fields in both the main form and the subform.

My initial intention of having the button in the subform and not in the parent form was to avoid having two boxes that list the same thing. I was trying to use the text box "Header SN Field" in the subform, which is bound to the "Header SN" field on the "Header Data" record table. This text box is what is used when a user wants to enter a new record, but I was trying to use the same text box for the search button as well.
Since my sub form is also used to enter data, I don't think I want the subform's bookmark/filter code to be on current event or on after update, since the user might be entering a new record instead of searching a record. If I want the button and text box to be on the subform, how do I reference the parent form and find the parent forms recordset? What do you mean by synchronizing the clone's bookmark with the parent form's bookmark? Can you give an example?

Thank you for all the help!