[Richard]

Ok, no two Newells are alike. Repeat that mantra.

Merge switch is on the dash, usually on the right. Usually.

Merge contactor is in the electrical closet on the passenger side of the engine bay. Some are in the front of the closet accessed from the side panel, and some are in the rear of the closet, accessed from the engine hatch. You will know it when you see it, and it will be labeled. Don't get it confused with the starter relay, which looks exactly the same. The big difference is the merge is continuous duty, and the starter intermittent duty.

No two Newells are alike. I can't tell you how many inside receptacles are daisied to one GFCI. On my coach the exterior/basement receptacles are on their own GFCI circuit.

There is usually a switch by the door that will disable all interior 12 VDC lights. It DOES NOT disconnect the house batteries. Newell will supply mechanical disconnects for the house and chassis batteries. BE AWARE, I have seen Newells wired two different ways on the house side. One way, one switch disconnects all the house loads EXCEPT the inverter. Another way has two switches on the house side, one for most loads, and one dedicated to the inverter. The point being, do not assume the master house switch kills the inverter power. It could be a shocking surprise.

Wait a year on your purchase. Right now prices are uber premium. Lots of folks buying used Newells with little idea of what they are getting into. When the pandemic eases, the new owners get a feel for yearly maintenance, and attention spans go elsewhere, the market will be filled with the coach you are looking for. It may need some neglected maintenance, but it will be out there at a far better price.