I have a Greyhawk 26Y with a generator removed and being serviced...my batteries only will charge now with shore power and not from the alternator. Serviceman says he thinks a battery disconnect switch is on...but I cant see of find such a thing and cant quite see how...I think when they took out generator to service they changed some wiring...help???
Typically the battery disconnect will be a switch near the door. Mine has a big red light that is lit when the battery is connected. If any of your 12 volt items work, such as lights, the problem is not the disconnect switch.
There probably is a relay on the firewall that connects the battery into the alternator charging circuit. Mine failed which caused your exact problem.
I have attached some docs that will aid in troubleshooting.
Retired electronic technician (45 years in the field)
2017 Greyhawk 29W
solar & many other mods
wife (maybe I should have given her top billing)