I think I understand your requirements, try this..
SELECT
count(tlkp_Defects.Defect_Title)
tbl_Assembly_Holds.Record_Date
FROM
tbl_Assembly_Hold_Defects
join tlkp_Defects on tbl_Assembly_Hold_Defects.Defect_ID = tlkp_Defects.Defect_ID
join tbl_Assembly_Holds on tbl_Assembly_Holds.TagNumber = tbl_Assembly_Hold_Defects.TagNumber
WHERE
tbl_Assembly_Holds.Record_Date BETWEEN '8/12/2009' AND '8/14/2009'
GROUP BY
tbl_Assembly_Holds.Record_Date
I have COUNTed the titles by date.
Also changed your join syntax to the more acceptable SQL92 standard.
Kev