if you want to include this new added field in search, modify catalogadvanced_search_result

replace this

$where_str .= "(pd.products_name like '%" . tep_db_input($keyword) . "%' or p.products_model like '%" . tep_db_input($keyword) . "%' or m.manufacturers_name like '%" . tep_db_input($keyword) . "%'";

with

$where_str .= "(pd.products_name like '%" . tep_db_input($keyword) . "%' or p.products_model like '%" . tep_db_input($keyword) . "%' or p.products_ref_const like '%" . tep_db_input($keyword) . "%' or m.manufacturers_name like '%" . tep_db_input($keyword) . "%'";


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