In script version >=v1.5.9 this feature should work by default or after entering your url in:

application\config\config.php

In script version <1.5.9:

In templates\bootstrap2-responsive\widgets\head.php replace http://maps.google.com with https://maps.google.com for frontend.

Same thing in: application\views\admin\components\page_head_main.php same thing.

In application\config\config.php , enter base_url with https:// prefix

If you want auto redirect this can be done by server configuration, please ask hosting provider or find option in your hosting admin interface.

For Hotel Booking / realocation:

File: templates\realocation\widgets\custom_javascript.php replace http://maps.google.com with https://maps.google.com for frontend.