The PCS device in Landmark 365 manages power consumption to fit within available power to the coach. So if you are trying to run 3 A/C units, dryer, microwave/convection, water heater, it will shed loads in a priority order to keep the most important stuff running during peak usage.
I would assume the Cyclone version is similar, but might not be as comprehensive. I think it allowed Heartland to get rid of the switch for running 2 of 3 A/C units, so it should be at least managing the A/C units to available power.
The PCS documentation describes a "limp home" mode (in the Landmark 365 model) so if there's a controller failure, you can still operate manually. I think when the cable is disconnected at the monitor end, it's in "limp home" mode. Details are sketchy, so that's partly guesswork.
Anyway, if your monitor is dark, but all the 120V appliances work, it might just be unplugged. If you find a connector that's disconnected, and plug it in, and stuff stops working, you'll want to unplug it again, call Heartland and get to your dealer to get the PCS equipment replaced.
