Just bought a new to us travel trailer. It has a Dometic americana absorption fridge (don’t know the model # off the top of my head but I can get it if needed). We plugged in and after a few hours now the fridge doesnt seem noticeably cooler, though the freezer kind of does. Fuses look good.
I typically turn mine on the night before and let it cool down overnight. Others will turn it on a full two days before the plan to leave. It can take time.
That said, if it doesn’t feel cool after a while, there are a few things that can affect proper cooling:
Make sure your RV is level
Check the thermostat (if you have one) and adjust if necessary
Check the door gasket to make sure it’s sealing properly
More likely than not, it just need smore time to cool down.