Hi Gordon548,
Welcome to the Heartland Owners Forum.
The slides and landing gear pull a lot of amps and need a well-charged battery to operate properly. Sounds like your battery is not getting charged by the Power Converter, or maybe was run down when you started the trip.
There's a 12V DC mini-circuit breaker between the Power Converter and battery. If that tripped for some reason, the battery will run down and not get a charge, except for a slow charge when the trailer is connected to the truck.
There's a buss bar with several breakers located near the battery. One has a teeny tiny reset button as pictured below. The breakers are usually covered with a red rubber boot.
It's also possible the Power Converter isn't working. The circuit breaker in the main panel could be tripped, or it could have come unplugged, or an on-board fuse on the converter might have blown. The converter is usually located behind the rear wall of the pass-through basement storage.
If you have auto-leveling, turn on the control panel and cycle it once to show voltage. If 13.2 V or higher while plugged into shore power, your Power Converter is working. If less, and you've pressed the reset button I mentioned, there's a problem with the Converter.
You can also refer to our owner-wittern
12V Block Diagram and Diagnostic Guide for more specific troubleshooting help.