No 12 VDC Cabin Power

Try to learn as much as you can about the 12 volt DC power system in your rig. It consists of a converter/charger that is powered by 110 volt AC "shore/camp" power and that keeps your "house batteries" charged . When you are running the rv generator , it charges the house batteries. When you are driving, the truck alternator charges the house batteries. You need to replenish battery electrolytes with distilled water to keep plates covered. Buy a rubber bulb-type battery filler. Buy a simple digital multimeter, read instructions, and learn to use it to check battery voltage and whether charging system is working properly. Also useful in basic troubleshooting. Find the 12 volt fuse panels and learn how to check for blown fuses. Learn about switching from shore power to RV generator for your particular rig. Learn proper procedure for starting, shutting down and re-starting RV generator and roof AC system. There are books etc. to explain all of the above and more.