Altering search results to handle a post meta field not working in current WordPress

I got this working through the following combination of functions (credit to this post):

function search_join_custom( $join ) {
    global $wpdb;
    if ( is_search() ) {
        $join .=' LEFT JOIN '.$wpdb->postmeta. ' ON '. $wpdb->posts . '.ID = ' . $wpdb->postmeta . '.post_id ';
    }
    return $join;
}
add_filter('posts_join', 'search_join_custom' );
function search_where_custom( $where ) {
    global $pagenow, $wpdb;
    if ( is_search() ) {
        $where = preg_replace(
            "/\(\s*".$wpdb->posts.".post_title\s+LIKE\s*(\'[^\']+\')\s*\)/",
            "(".$wpdb->posts.".post_title LIKE $1) OR (".$wpdb->postmeta.".meta_key='YOUR_KEY_NAME' AND ".$wpdb->postmeta.".meta_value LIKE $1)", $where );
    }
    return $where;
}
add_filter( 'posts_where', 'search_where_custom' );
function search_distinct_custom( $where ) {
    global $wpdb;
    if ( is_search() ) {
        return "DISTINCT";
    }
    return $where;
}
add_filter( 'posts_distinct', 'search_distinct_custom' );