My Dometic refrigerator model RM 3663 does not cool as well as it should. I have it set as high as it goes. Freezer is very cold but the refrigerator part only keeps the beer drinking cold.  Checked back and see no blockage, etc.  Does not appear to be any leaks.  Dealer that use to work on it sold out so no one close by. 

Any suggestions is appreciated.

If you open the lower fridge vent cover on the outside of the trailer, you will see most of the mechanicals of the appliance. There will be many wires routed to various parts, and at first they can be quite confusing.

There are a few electrical boards affixed to the fridge that include several push on types of electrical connectors. After a few years of the elements, the contacts can become corroded, which changes the electrical values going to the various components.

With the power off, it is an easy matter to pull one at a time, clean the terminal, add some dielectric grease to the area, and push the terminal back into place. A pair of needle nose pliers will make the job a bit easier. By removing and replacing one terminal at a time, there is no fear of improperly replacing the wires.

Also, with an ohm meter, the resistance of the electric heater can be determined, and by checking that with published specifications, it can be resolved whether it is working properly or not. There are two wires going to the heater, both terminated to a board. Pulling one of them allows you to check the resistance between them.

Nearby to the circuit boards is a small metal plate, usually held into place with a couple of screws. This covers the gas supply and burner assy. With it removed, you can visually check the gas flame, burner, thermocouple etc,. After starting the fridge on a gas cycle, you can easily visually check the flame for strength, colour and shape. This is the area often messed up with bugs and dirt that adversly affects the fridge's opperation. By ensuring the area is clean, many problems can be resolved.

The overall area around the fridge can also be inspected. Insulation, rigid panels and fasteners can be checked, to make sure everything is in place and not dislodged by the road vibration it regularly receives. You will usually find an accumulation of road dust, which should be cleaned out with a vacuum cleaner. An air hose also helps, but don't use it directly on the burner's orfice.

These checks can be easily accomplished by a novice in less than an hour. If the fridge was working when it was stored, usually a "tune up" is all that is necessary to restore it again to a working condition. Checking things yourself, saves a considerable effort to take the trailer to a repair facility, and a great deal of money in labour charges. If the problem is not resolved with these actions, you've done no damage, and have reduced the trouble shooting necessary by the mechanic.

On line prints are available for most fridges, that include components, wiring diagrams and trouble shooting efforts. Most replacement parts are also available on line.