[Pull Toy]

Any reverse polarity, even if just for a second, is enough to trip any protection devices. I'd try to manually reset all breakers, and check all fuses, including any in-lines, and check the converter. Come off of shore power and see if you still have 12v. on battery alone. Then come off of battery, and see if your 12v appliances will work off of only shore power. I'm not familiar with your arrangements, but also check for a battery disconnect switch. But be aware that even if turned off, some 12v will still be present at some equipment , like your CO detector and hard wired smoke detectors etc.

The fact that the 12 volt lights work, may not indicate that there is enough amperage to power the slider. I would check the state of the disconnected battery charge with a multi meter. If you don't have one, Auto Zone, NAPA etc, will test it for free.

Good Luck,