mypros+
Error code reference

Atwood Refrigerator Error Code CHECK+AUTO+GAS+AC+DC ON

Open thermal switch on heat source (canister above burner box reached abnormally high temperature, thermal…

Atwood codesAtwood refrigerator codes

Open thermal switch on heat source (canister above burner box reached abnormally high temperature, thermal switch opened).

First step from the service manual

Check thermal switch on canister above burner box; all power source outputs (AC relay and GAS valve relay) are disabled.

The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.

MyPros+ Max

Get the full diagnostic procedure for CHECK+AUTO+GAS+AC+DC ON.

  • Step-by-step tests with expected resistance, voltage, and continuity values
  • Wiring diagram references and connector pinouts from the OEM service manual
  • Verified part numbers when replacement is required
Get the full procedure

$29/month · Cancel anytime · Or $9.95 3-day pass

What CHECK+AUTO+GAS+AC+DC ON means on a Atwood refrigerator

The CHECK+AUTO+GAS+AC+DC ON display on an Atwood refrigerator indicates that the thermal switch mounted on the canister above the burner box has opened due to abnormally high temperature. This thermal switch is a protective safety device designed to interrupt operation when heat levels in that area exceed safe limits. When the switch opens, the control board responds by disabling all power source outputs simultaneously, including the AC relay and the GAS valve relay. This means the refrigerator cannot operate on any of its available power sources until the fault condition is addressed.

The thermal switch functions as a one-time or resettable safety cutout depending on the specific switch type installed. Its location above the burner box makes it directly exposed to the combustion and heat exchange area. If combustion is inefficient, airflow through the burner compartment is restricted, or the flue system is partially blocked, heat can accumulate in the canister area and cause the switch to open. A failed switch that trips at lower than normal temperatures is also possible, though less common than actual overheating conditions.

Because all three energy modes (AC, DC, and gas) are disabled when this code is active, the refrigerator will not cool or maintain temperature until the fault is cleared. Technicians should inspect the thermal switch on the canister for continuity, check the burner box area for obstructions or soot buildup, and verify that the flue and ventilation path are clear before restoring power and attempting to restart the unit.

Source: manufacturer service documentation.

Common causes of CHECK+AUTO+GAS+AC+DC ON

  1. 01

    Restricted Burner Box Ventilation

    Wiring / connection

    Blocked vents, debris, or insect nests in the burner compartment can trap heat around the canister, causing the thermal switch to open. Inspect the exterior vent cover and interior burner box area for any obstructions.

  2. 02

    Flue or Exhaust Blockage

    Wiring / connection

    A partial or full blockage in the flue tube prevents combustion gases and heat from escaping, which causes heat to back up into the canister area. Check the flue path from the burner through the roof vent for soot buildup or physical obstructions.

  3. 03

    Faulty Thermal Switch

    Part replacement

    The thermal switch itself may have failed and is opening at temperatures below its rated threshold. Test the switch for continuity at ambient temperature; an open reading at room temperature confirms a failed switch that needs replacement.

  4. 04

    Inefficient or Dirty Burner

    Wiring / connection

    A burner with clogged orifices or improper flame characteristics produces excess heat or incomplete combustion, which can elevate temperatures in the canister area beyond normal limits. Inspect the burner orifice and flame pattern for irregularities.

  5. 05

    Improper Refrigerator Leveling or Installation

    Wiring / connection

    An out-of-level installation can affect the absorption cooling cycle and alter heat distribution in the burner area, potentially contributing to localized overheating. Verify the unit is within the required level tolerance for proper operation.

See the test procedure for each cause

Frequently asked questions about CHECK+AUTO+GAS+AC+DC ON

What does CHECK+AUTO+GAS+AC+DC ON mean on a Atwood refrigerator?
This error indicates that the thermal switch located on the canister above the burner box has opened because the temperature in that area reached an abnormally high level. As a safety response, the control board disables all power source outputs, including the AC relay and the GAS valve relay, so the refrigerator cannot run on any power mode. The root cause is typically overheating due to restricted airflow, a flue blockage, a dirty burner, or a failed thermal switch. The fault must be diagnosed and corrected before the unit will return to normal operation.
How do I fix the CHECK+AUTO+GAS+AC+DC ON error on my Atwood refrigerator?
Begin by inspecting the thermal switch on the canister above the burner box and testing it for continuity. If the switch reads open at room temperature, it has failed and needs to be replaced. If the switch tests good, check the burner compartment vents, flue path, and burner orifice for blockages or debris that may have caused genuine overheating. Clearing any obstruction and verifying proper airflow through the compartment is often enough to resolve the condition once the switch is confirmed functional or replaced.
Is the CHECK+AUTO+GAS+AC+DC ON error on an Atwood refrigerator a safety concern?
Yes, this error represents a legitimate safety shutdown. The thermal switch opening signals that temperatures in the burner area reached an unsafe level, which could indicate a combustion or ventilation problem. Operating the refrigerator without resolving the underlying cause could risk component damage or a fire hazard in an RV or marine environment. The system is designed to disable all power modes specifically to prevent further operation until the issue is corrected.
Will resetting the Atwood refrigerator clear the CHECK+AUTO+GAS+AC+DC ON error?
Simply resetting or power-cycling the unit may temporarily clear the error code, but the fault will return if the underlying cause of the overheating is not corrected. If the thermal switch has opened due to a real overheating event, the heat source that caused the trip must be identified and resolved first. If the thermal switch itself has failed, it must be replaced before the unit will operate reliably. Always diagnose the root cause before relying on a reset.
How much does it cost to repair the CHECK+AUTO+GAS+AC+DC ON error on an Atwood refrigerator?
Repair costs vary depending on the cause. If the fix involves only cleaning the burner, clearing a vent blockage, or removing a flue obstruction, the cost may be minimal, covering only labor time. If the thermal switch itself has failed and requires replacement, parts and labor typically range from around $50 to $200 depending on the service provider and part availability. More complex issues involving burner components or control board problems would increase that estimate.

Related Atwood refrigerator codes

All Atwood refrigerator codes
View all 11 Atwood refrigerator codes

78,000+ service manuals · 160,000+ error codes · 55+ brands

Get Started

$29/month · Cancel anytime · Or $9.95 3-day pass