You will need the Installation and Service Manual, it should be with your motorhome documentation. If not, contact firstname.lastname@example.org
As far as needing 12VDC, the answer is yes. The manual has a complete trouble shooting process outlined. It is fairly complex and not something I can post here. If you are unable to locate the manual from Intellitec, send me a message with your email and I will send you a PDF. Just be sure to tell me what you want.