Ignore search term

I want to use my custom search page as a browse page, that means i want to have it ignore the search term, and instead just return posts from within a custom post type and grouped by custom taxonomy.

Is this possible? Everytime i omit the search term, it returns nothing.

This is what I have so far:

$search_types = isset($_GET['types']) ? $_GET['types'] : $post_types[0]['type']; // e.g. shoppinglist
$query->query_vars['s'] = $search_term;
$query->query_vars['taxonomy'] = 'fruit';
$query->query_vars['term'] = 'oranges';
$query->query_vars['posts_per_page'] = 5;
$query->query_vars['operator'] = 'or';
$query->query_vars['post_type'] = array($search_types);
$query->query_vars['paged'] = get_query_var( 'paged' );
relevanssi_do_query($query);

with a $search_term works, without doesnt, how do i get it to just return all ‘shoppinglist’ post_types which are tagged ‘oranges’ from the ‘fruit’ custom taxonomy.

http://wordpress.org/extend/plugins/relevanssi/