How to Fix a Dometic Refrigerator Not Cooling

Dometic refrigerators are designed specifically for RV owners, offering features such as secure door locks to prevent the doors from opening during travel and the ability to run on multiple power sources, including propane and electricity.

Due to these specialized features, when Dometic refrigerators experience problems, they can be a bit more challenging to repair than regular domestic refrigerators. This article will discuss the most likely causes of a Dometic refrigerator not cooling and provide step-by-step instructions to help you fix the issue.

Here’s how to fix a Dometic refrigerator not cooling:

1. There’s an issue with the thermistor

A common problem with Dometic refrigerators that results in the appliance not cooling is an improperly positioned or faulty thermistor. The job of the thermistor is to monitor and regulate the fridge’s temperature, so when it doesn’t work properly cooling issues can occur.

The thermistor is located in a clip that attaches to the cooling fins inside the refrigerator at the back. The thermistor must be at the top of the clip, and the clip should be placed on the upper half of the cooling fins to work properly.

However, sometimes the thermistor can slip down to the bottom of the clip, and the clip can slip down to the bottom section of the cooling fins, likely due to vibrations during travel or accidentally being knocked.

If your thermistor or its clip has slipped out of position, reposition them correctly. Many people use additional tape and a binder clip to fasten them in the correct position more securely after experiencing this problem.

When it comes to a faulty thermistor, you can test and replace them by following these steps:

1. Access the back of the refrigerator by removing the access panel on the exterior of your RV.
2. Unplug your Dometic refrigerator for safety.
3. Remove the cover on the control board. You will likely need a screwdriver.
4. Disconnect the thermistor wire from the control board.
5. Set a multimeter to ohms, then press its probes against the thermistor’s terminals.
6. At room temperature, you should get a reading of about 2000 ohms for most thermistors. However, it’s best to check your refrigerator’s manual for the expected value.
7. Next, place the thermistor in a glass of ice water and wait a few minutes. You should get a reading significantly higher, around 9500 ohms for most models.
8. If the readings you get deviate significantly from this, or you get a no resistance or zero ohms reading, replace the thermistor.
9. Replacing the thermistor is simple. Order a new compatible part and plug it into the control board where the old one went.

2. There’s an issue with the power or gas supply

Some people experience cooling issues only when the refrigerator is running on gas, while others when it’s running on electricity. If this is the case for you, you can check the power and gas supply by:

Gas

Check that there is propane in the tank and that the valve is fully open. Use soapy water to check the gas line for leaks. Inspect the burner to see if it is clogged with dirt and clean it if necessary. Ignite the burner and check that there is a steady, blue flame.

Electric

Use a multimeter to check that the outlet is supplying 120 volts. Ensure that the circuit breaker for the appliance hasn’t tripped. Inspect the power cord on the unit for signs of damage and replace it if necessary.

3. There’s an issue with the cooling unit

Dometic refrigerators use an ammonia-based refrigerant in the cooling unit. Sometimes this refrigerant can leak, resulting in the refrigerator no longer cooling properly.

You can check for this by removing the access panel on the exterior of your RV. Then, you can perform a visual and smell check. Look for any yellowish residue on the cooling unit and see if you notice an ammonia smell. The cooling unit looks like a series of metal coils or tubes.

If you can smell ammonia or see the yellowish residue, you most likely have a leak and you will need to call in a professional to repair or replace the cooling unit safely.

4. The refrigerator is not level

When running a Dometic refrigerator, your RV should be reasonably level, otherwise you risk damaging the cooling unit and experiencing cooling issues as the refrigerant cannot circulate properly.

However, as long as your RV is level enough that you feel comfortable walking around inside it, it should be okay for your Dometic refrigerator.

5. The gaskets are dirty or damaged

The gaskets create an air-tight seal around the doors, ensuring warm air cannot enter and cold air cannot escape. However, if the gaskets are damaged or dirty, the opposite will happen, meaning the refrigerator must work harder to maintain the right temperature or may fail to do so.

You can clean a dirty gasket using warm soapy water and a soft brush or sponge. However, if the door gasket is damaged, such as cracked or worn with visible gaps, it will need to be replaced.

Replacing the door gasket is relatively simple. It involves ordering a compatible replacement, removing the old one, and carefully installing the new one in its place. Some gaskets are push-in, whereas others are adhesive-backed. For adhesive-backed gaskets, you will need to use a solvent to remove the old adhesive when removing the original gasket.

6. There’s an issue with the control board

A faulty control board can also cause the refrigerator not to cool. Sometimes, temporary glitches can be resolved by resetting the appliance. You can do this by unplugging the unit, waiting one minute, then plugging it back in.

You can also inspect the control board via the access panel on the exterior of your RV for signs of damage, such as burn marks, cracks, corrosion, or loose connections.

Other than that, diagnosing, fixing, or replacing a faulty control board generally requires the help of a professional technician as it’s quite a complex job. You also don’t want to replace this expensive component unless you’re entirely sure that it’s faulty.