BT 5231 engine not charging coach battery

[butter-GSO]

My owner's manual states that when the engine is running it will charge the coach battery. My meter shows that is not happening. Please advise, thank you.

 

[Leisure Time Larry]

It could be a few things. Watch these videos to familiarize yourself. Good luck!

https://youtu.be/wc_vGNHhAYE

https://youtu.be/FWFNMt_DkpM