Should Coach lights be hooked up to chassis battery?

[DON]

I have a 76 winnebago chieftain.  We just hooked in a battery cutoff to the coach.  All coach seems to be off after unhooking battery.  As I turned key off, I noticed a light go off out of the corner of my eye.  After investigating, it seems that some front interior lights are controlled by the engine battery.  Is there a purpose for this?  I do not have a shutoff connected to the engine battery.  If you have these front interior lights on, when you turn the key off, the lights go out.  I think this is the way it is supposed to be, just not sure why. Thanks in advance.

[Sasquatch]

If Winnebago was anything like many other coaches in the early/mid 70's, they wired the coach/chassis batteries differently than modern coaches.  Or, a previous owner could have modified things.

My Executive (1976) was wired where the "House" battery (big bank) ran the house and started the engine plus ran the engine electrical systems.  The small secondary battery was ONLY for the generator.  When I redid the electrical system to modernize it I set it up so that the chassis battery started and ran the engine as well as the generator, and the house bank was just for the house.  I used a continous duty relay to join the banks when the engine was running so both would charge.  This allowed me to use true deep cycle batteries (2x 6vdc) for the house, and a massive 1000 cca battery for starting. 

But, there is some crossover between the circuits because of how it was originally set up and 43 years of working on it.  Get a set of wiring diagrams and trace your battery banks and how they are wired together.

[Elandan2]

Generally, Winnebago kept the chassis circuits supplied from the engine battery and the coach circuits from the auxiliary battery. There are definitely exceptions though. On ours, the light in the trunk is powered from the chassis side and wired through the ignition side. That way, the light will always turn off with the engine off and not drain any batteries. A good idea is to email Winnebago and request the wiring diagrams for your coach. Unfortunately, the older coaches are not available online.