Today I was told by my RV dealer (will be picking up new trailer next week) that fords are the one brand that in order to charge your trailer battery while driving you need to have a special part (cannot remember the name) plugged into the fuse box so the battery will charge. I guess it is a safety feature so your truck battery doesn’t accidentally get drained if you forget to unplug at the camp site. Im wondering if I got the heavy duty tow package, does this already come with the truck or do I still need to order it and install? I have a 2022 ford expedition limited SSP with HD tow. Thanks!