ServiceNomad RV · Knowledge
RV Fridge CHECK Light Is On
The CHECK light on an RV refrigerator indicates the control board has detected a fault condition and shut down cooling operation. This is a diagnostic feature found on most modern RV absorption refrigerators (Dometic and Norcold). Unlike a simple pilot-out condition, the CHECK light means the refrigerator attempted to operate, encountered a problem, and entered a fault mode. Understanding what triggers the CHECK light helps you determine whether it's a simple reset issue or a deeper problem requiring professional attention.
What the CHECK Light Means
RV refrigerators with electronic controls constantly monitor operating parameters like flame presence (gas mode), heating element current (electric mode), and refrigerant temperatures. If the control board detects an abnormal condition—such as no flame when it expects one, excessive current draw, or failure to cool—it will shut down and illuminate the CHECK light as a warning. Some refrigerators also display a fault code (a series of blinks or a numeric code on the control panel) that provides more specific information about what failed. Always note the code before resetting, as it helps a technician diagnose the problem quickly.
Gas Mode CHECK Light Causes
When running on propane, the CHECK light most commonly indicates the burner failed to ignite or the flame went out unexpectedly. This can be caused by: low gas pressure (empty tank or failing regulator), a clogged burner orifice, a failed igniter or gas valve, or a dirty flame sensor that cannot detect the flame even though it's burning. Wind and airflow issues can also cause flame-out—if the refrigerator vent is located on a windy side of the RV, strong gusts can blow out the burner flame, triggering the CHECK light. A baffle or vent cover can help in these situations.
Electric Mode CHECK Light Causes
When running on 120V electric mode, the CHECK light typically indicates a problem with the heating element circuit. Common causes include a burned-out heating element (open circuit), a tripped high-limit thermostat (from overheating), low input voltage (below 108V), or a failed relay on the control board that switches the heating element on and off. A technician will test the heating element resistance (typically 300-400 ohms for a 350-watt element) and verify that 120V is reaching the element when selected. They'll also check the high-limit thermostat on the boiler tube, which can trip if the refrigerator overheats and must be manually reset.
Control Board and Sensor Failures
The CHECK light can also indicate a failed control board, faulty thermistor (temperature sensor), or communication error between the control board and user interface. These are less common but possible, especially in refrigerators that have been exposed to voltage surges or moisture intrusion. A technician will test the thermistor resistance (should change predictably with temperature) and inspect the control board for burnt traces, failed relays, or capacitor bulging. If the board is failed, replacement is necessary—boards are model-specific and must match the refrigerator exactly.
⚠️ Safety Notes
- Do not repeatedly reset the CHECK light without addressing the underlying cause—this can lead to propane buildup (in gas mode) or overheating damage (in electric mode).
- If you smell propane or detect gas near the refrigerator, turn off the propane supply immediately and call a technician.
💡 Prevention Tips
- Clean the burner assembly and flame sensor annually to prevent gas-mode CHECK light issues.
- Ensure adequate ventilation airflow behind the refrigerator—blocked vents can cause overheating and electric-mode faults.
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