diff --git a/lisp/help-fns.el b/lisp/help-fns.el
index 9a6225d8589..0cb2c6d5d77 100644
--- a/lisp/help-fns.el
+++ b/lisp/help-fns.el
@@ -592,6 +592,8 @@ the C sources, too."
            (start (point)))
        (seq-do-indexed
         (lambda (entry level)
+          (when (symbolp map)
+            (setq map (symbol-function map)))
           (when-let ((elem (assq entry (cdr map))))
             (when heading
               (insert heading)