Remove the inside trim and you should have access to the control box.
Wires include, 120vac, black pair to freeze sensor, bundle from thermostat, blue/white to control furnace, and some black/white paired wires that carry 12vdc.
The 12v wires should be attached with a crimp connector to the harness. Get your voltmeter on those wires to check voltage.
Paired white/black are 12v supply.
Blue/white is control connection to furnace.
Yellow is 120v power bundle.
Black to the left is the freeze sensor.
Brown is the bundle from the thermostat.

Or maybe your Dometic is completely different.