This actually is a fairly common failure with the SDC-107A Battery Control Center. There is a heavy duty contactor that fails.
The vendor is reported as very helpful but with it being a holiday weekend they may not be available. There is troubleshooting information at the bottom of the product page: https://rvcustomproducts.com/sdc-107a
Bubbles may remember since he posted a link in this older thread: https://www.forestriverforums.com/fo...7a-244357.html
A few people simply found an equivalent at a local auto parts store.
Be DARN certain to take a picture and label all wires before taking the old one out. Also be DARN certain to take precautions about a cable shorting to ground or you can cause a fire and serious personal injury.
Until you get it repaired just run the generator while driving. If the house batteries are connected the generator will power the converter and charge the house batteries.