[BB_TX]

If the 120 vac and the 12 vdc are both “blinking” at the same time (and by blinking I assume a momentary lose of power) then my guess would be the following. One, your battery(s) is bad and not supplying good 12 volts. Two, the converter is supplying the 12 vdc. And three, you are momentarily losing 120 vac power causing the converter to momentarily also drop out, and losing both the 120 AC power and 12 vdc momentarily at the same time. That would suggest a loose or bad connection to shore power. That could be a problem at the park outlet, a problem with your power cord, a problem at the trailer connector where your cord plugs in (some of those reported lately), or a problem in your distribution panel.