14th Oct 2026
Dometic Americana Not Cooling Well on AC or Gas: Troubleshooting Flowchart
WARM ON ALL MODES
Dometic Americana Not Cooling Well on AC or Gas
The fridge runs on both AC and propane, but it won’t get cold enough on either one. Since both heat sources work, the problem is usually how well the fridge gets rid of heat or holds the cold: leveling, venting, door seals and how it’s loaded. After that, test the thermistor and the cooling unit itself.
Dometic Americana & Americana Plus · RM2351 through RM2862
Fits these models
Different model? These steps are for the models above, from Dometic’s service manual for them. For any other Dometic fridge, ask a tech before you test or order parts.
Before you start
- Why it matters. An absorption fridge has no compressor or pump. It relies on gravity, heat and airflow, so leveling and venting affect it far more than a home fridge.
- Where things are. The cooling unit, vents and lower circuit board are behind the lower outside vent. The thermistor is clipped to the fins inside the fridge.
- You’ll need a thermometer, a dollar bill, a multimeter set to ohms, and a glass of ice water.
PART A · LEVEL, LOADING & SEALS
The easy fixes first.
STEP 1
Check the leveling
When parked, the RV only needs to be level enough to be comfortable to live in, with no noticeable slope to the floor or walls. Out of level, the refrigerant collects in the cooling unit and the cooling stops. While driving, leveling doesn’t matter.
Is the RV level?
Level the RV
Level it and give the fridge a few hours to recover. The more level it is, the better it works.
STEP 2
Check the food storage
Cold air has to move freely inside. Shelves covered with foil, trays or packed food block the airflow and the fridge runs warmer.
Is the airflow blocked?
Rearrange the food
Uncover the shelves and leave space between items, then check the temperature again in a few hours.
STEP 3
Test the door seals
Close each door on a dollar bill and pull it out. Do this on all four sides in several places. You should feel resistance every time. Also check that the doors aren’t closing too high or low against the frame.
Did it slide out easily anywhere?
Fix the seal
Lift the inside of the gasket and put a 1/4-inch ball of fiberglass insulation in each corner of both doors, especially the top corners. Warm the gasket with a hair dryer (don’t melt it), close the door and let it cool. If it still won’t seal, replace the gasket. A door sitting too high or low can be adjusted with a thin washer on the hinge pin.
STEP 4
Check other air leaks
Look at the drain hose behind the fridge. It needs its check valve at the end; if the hose was shortened at install, the valve has to be moved to the new end. Also check that the cooling unit’s foam block sits flush against the back of the cabinet.
Did you find a leak?
Seal it
Put the check valve back on the end of the drain hose, or reseat the cooling unit so the foam block seals. Leaks also cause fast frost buildup.
PART B · VENTING
The fridge has to get rid of the heat it pulls out.
STEP 5
Check the venting
Behind the lower vent, look up past the cooling unit toward the roof or upper side vent. There should be no gap at the sides and top of the fridge, less than 1 inch between the back of the fridge and the outside wall, and baffles blocking any dead air pockets. Clear out nests, leaves and debris.
Is the venting correct and clear?
Fix the venting
Remove anything blocking the airflow and add baffles where heat can get trapped. Follow Dometic’s vent instructions, form 3308666. A fridge that gets warmer as the outside temperature rises is usually poorly vented or has a weak cooling unit.
PART C · THERMISTOR & COOLING UNIT
Everything around the fridge is right. Test the parts.
STEP 6
Test the thermistor
Unplug the thermistor from P2 on the lower board. Put it in a glass of ice water (more ice than water, about 33–35°F) for 8 to 10 minutes. Measure ohms across the two wires from the wire side.
Is it about 8,000 to 10,000 ohms?
Replace the thermistor
A bad reading can shut the cooling off too early. Replace it with the Thermistor 3851210025 or the Thermistor Kit 38510590422, which includes the plug and holder.
STEP 7
Test the cooling unit
First make sure the AC heater reads the right ohms, and the venting and leveling are good. Put about a gallon of water in containers inside the fridge, with a thermometer in one of them. Leave the thermistor unplugged so the fridge runs nonstop, and let it run on AC for at least 12 hours.
Is the water 43°F or colder?
Replace the cooling unit
The cooling unit is weak. It’s sealed and can’t be repaired, so it has to be replaced. See our Dometic cooling units or ask a tech with your model and product number.
The cooling unit is good
Plug the thermistor back in. Hot weather lowers how cold any absorption fridge can get, so recheck the venting. If it works for 2 to 5 days and then warms up, run this test for 24 to 48 hours. Some units fail only after running a while.
Still stuck? ask a tech with your model, product number and the readings you got. We’ll confirm the part before you order.
Covers the Dometic Americana and Americana Plus: RM2351, RM2354, RM2451, RM2454, RM2551, RM2554, RM2652, RM2662, RM2663, RM2852 and RM2862. Based on the Dometic RM2xxx service manual, Diagnostic Flow Chart, Symptom 5: Insufficient cooling on all modes.