DC battery terminals crossed, new control panel

I did what I call a brain fart move while I was not paying attention and crossed the battery terminals reverse polarity. It led me to upgrade and replace the AC/DC control panel. So, wire for wire, one at a time, I replaced the new box. All the AC side works better than ever but the DC side powers on the fan for a moment and then the light shuts off. Now I have been told about reverse polarity fuses but mine are not blown because this is a new system. I have an 1995 Alfa Leisure 35ft 5the wheel and I cannot find an owner's manual anywhere online. Any help?