SN 6400 Batteries - Which is Chassis, which is coach

[LTC_R]

I just purchased a 2008 SN 6400 a month ago, what a great upgrade from my 1996 micro Mini C on a Toyota chassis. I love this thing but it isn't starting well. Everytime I go to start it, I have to use the emergency start to kick in the coach batteries to assist in getting it started. I went to have the batteries checked, and the guy, not much help, said he wouldn't be able to look into it for a week or two - I don't think he really wanted to get involved in what he could tell was going to be a project. I am not sure which 2 batteries are for the Coach, and which 2 are for the chassis. I am getting educated fairly quickly on electrical systems, but would really appreciate any ideas on which are which. From tracing the wiring, I really can't tell, once it goes into the mystery black wire covers. Is it the front two or the rear two? Thanks in advance for any ideas, help, and past experiences.

I suspect I will become a frequent visitor to this forum site, lots of great people out there. Thanks in advance.