Dometic Refrigerator E3 code

So I’ve disconnected 120v AC power to the trailer and have only 12v power feeding the trailer. I tried disconnecting 12v power for a few minutes but as soon as I restore 12v power I immediately get the E3 error code. I only know of two fuses on the 12v side. One inline 4 amp and one mini 5 amp in the circuit board. Both fuses test good. I know I have 12 volts feeding the control board, I know the fuses are good, but still get the E3 code. I don’t see any type of reset button and since I have the display reading E3 and 12v power to the circuit board, I don’t think a reset button, (if there was one) is my problem. Unless someone can steer me in another direction, or tell me something different to check, I think my next move is to spend the $200 and buy a new circuit board. Thanks for the suggestions and if anyone has any more, I surely welcome them.