2008 Seneca 36MS on Kodiak chassis

[Motorhome1]

I am trying to diagnose an 12 volt electrical problem on my Seneca. I have contacted Jayco for specific wiring diagrams, but they said they only maintain them for models 5 to 7 years old. I have seen portions of the diagrams here on the forums. But I am missing something. It is the oddest thing, I have replaced the converter due to it not charging coach batteries, coach batteries
are new, confirmed both the latching relay is good and the 50 amp thermal circuit breaker is good. 12 volt system is functional with shore power, unplug and the shore power and the entire coach system is dead. Start the chassis, engage the emergency start relay and the 12 volt coach system is back alive. Shut off engine which opens that emergency start relay again. Coach 12 volt system is dead again. The only thing I can think of is there is another breaker between the latching relay and the load center.

[Superseneca]

Did you check the house battery disconnect switch and relay?

[Motorhome1]

I have tested that portion, I have confirmed that latching relay is working and allowing power to pass through. I also have replaced the 50 amp thermal circuit breaker also. In desperation I have moved both wires on the latching relay to same side and also wires on circuit breaker to same side. Still now power from coach batteries. One other thing, when I start the chassis and the emergency 225 amp start relay closes. I have lights and 12 volt systems. I disconnect large wires coming from relay to coach batteries. Whole 12 volt system shuts down.

[RVermont]

I am not sure if this could be a problem but I wonder if you lost the ground connection somewhere. If the power is only working when the chassis batteries are connected I wonder if they are providing the power and the ground required when connected. When they are not in the circuit the power from the battery would not have anywhere to go if a ground was off somewhere.

[Motorhome1]

Interesting, you could be on to something. I will confirm all grounds of coach batteries. Thank You

[mjc29]

here is what i got for my 2008 34ss see if it will help you

[Rustynuts]

Not sure what converter you have but on our 2018.5 with the PD4590 we had a no charge issue and I finally traced it to a broken ground using the PD troubleshooting guide. I'll post it here but I think you may have a different one.

[Motorhome1]

Thanks to you all for your valued answers. There is a wealth of knowledge here. RVermont hit it out of the park. It turns out the the frame ground was loose. That is why it would work while using the converter with shore power because it has its own ground and also when the chassis batteries were coupled to coach batteries during the use of the emergency start button. The chassis batteries have there own ground.
Thank You for all of the information!

[SANTARA]

Sent P.M today.