My Dometic 2652 is not cooling properly. I contacted Dometic customer service and found out it is not properly vented, the necessary baffle is not in place, so the entire refrig compartment is heating up instead of the heat exiting through the roof vent. My unit has no fans. I intend to make a simple baffle and install it myself, even though refrig is still under warranty. I don't want to leave it at the dealer for 3 weeks for a simple repair. I figure I can install my own vent for next to nothing.
Below is a link to the Dometic Installation guide. Be sure to look it over thoroughly to make sure you have the correct model number and vent type. It makes a difference depending on the dimensions and on type of vent system installed. It can be roof vented, or side panel vented with either a single side vent, or double side vent.
I hope this helps.