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Error code reference

Atwood Refrigerator Error Code CHECK ON + AC ON (AC No Supply)

AC mode selected but no AC supply is available; 250ms beeper sounds.

Atwood codesAtwood refrigerator codes

AC mode selected but no AC supply is available; 250ms beeper sounds.

First step from the service manual

Verify 120VAC line and neutral connections at J9 and J11; check AC supply availability.

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

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What CHECK ON + AC ON (AC No Supply) means on a Atwood refrigerator

The CHECK ON + AC ON condition on an Atwood refrigerator indicates that the control board has been set to AC operating mode, but the unit cannot detect a valid 120VAC supply at its AC input terminals. When this condition is present, the board triggers a 250ms repeating beeper alert to notify the user or technician that the selected power source is unavailable. The refrigerator cannot operate in AC mode without a confirmed line voltage presence, so cooling via AC power is suspended until the issue is resolved.

The AC power input to the Atwood refrigerator control system routes through connector J9 and connector J11 on the board. J9 typically carries the hot line connection while J11 carries the neutral. If either connection is absent, loose, corroded, or improperly terminated, the board will not register an AC supply even if power is present at the source. The control logic monitors these inputs continuously, and any interruption will immediately trigger this alert condition.

Common root causes include a tripped circuit breaker or blown fuse upstream of the unit, a failed shore power connection in RV or mobile applications, loose or oxidized wiring at J9 or J11, a damaged power cord, or a failed AC inlet receptacle. In some cases, the mode selector may have been inadvertently set to AC while the unit is running solely on DC or LP gas power, making the error appear even though the unit is otherwise functioning. Diagnostic work should begin at the source voltage before moving to the board connectors.

Source: manufacturer service documentation.

Common causes of CHECK ON + AC ON (AC No Supply)

  1. 01

    Tripped breaker or blown fuse

    Wiring / connection

    A tripped circuit breaker at the panel or a blown inline fuse upstream of the refrigerator will cut AC supply entirely. Check the breaker panel and any fusing in the supply circuit before inspecting the unit itself.

  2. 02

    Loose or disconnected wiring at J9 or J11

    Wiring / connection

    The line and neutral conductors connect to the control board at connectors J9 and J11. If either terminal is loose, pulled out, or corroded, the board cannot detect AC presence even when voltage is available at the source.

  3. 03

    No shore power or AC source available

    Wiring / connection

    In RV or mobile applications, the unit may have been set to AC mode while disconnected from shore power. Confirm that a valid 120VAC source is actually connected and energized at the pedestal or outlet.

  4. 04

    Damaged power cord or AC inlet receptacle

    Part replacement

    Physical damage to the power cord, a broken prong, or a failed AC inlet receptacle can prevent voltage from reaching the board terminals. Inspect the cord for cuts, burns, or bent contacts and test continuity.

  5. 05

    Incorrect mode selection

    Wiring / connection

    If the unit was manually set to AC mode while only DC or LP gas power is available, this alert will appear even though the refrigerator may otherwise be operating normally. Switching the mode selector to match the available power source will clear the condition.

See the test procedure for each cause

Frequently asked questions about CHECK ON + AC ON (AC No Supply)

What does CHECK ON + AC ON (AC No Supply) mean on a Atwood refrigerator?
This error indicates the refrigerator's control board is set to AC operating mode but cannot detect a 120VAC supply at its input connectors, J9 and J11. The board triggers a 250ms repeating beeper to alert you to the missing power source. AC cooling is suspended until a valid line voltage is detected. The most common causes are a tripped breaker, missing shore power connection, or a loose wire at the board connectors.
How do I fix the AC No Supply error on my Atwood refrigerator?
Start by confirming that a 120VAC source is connected and energized, and check the circuit breaker or fuse supplying the unit. Next, inspect the wiring at connectors J9 and J11 on the control board for loose, corroded, or disconnected terminals. If the source voltage and connections are intact, check the power cord and AC inlet for damage. If the unit is in a mode that does not match the available power source, switching the mode selector should resolve the alert immediately.
Is the AC No Supply error on an Atwood refrigerator a safety hazard?
The error itself is a control board notification rather than a safety fault. However, if the root cause is a damaged power cord, failed receptacle, or wiring issue at the board, those conditions should be addressed promptly to prevent potential shock or fire hazards. Do not bypass or ignore persistent wiring faults. If you are unsure about working with 120VAC wiring, consult a qualified technician.
Will resetting the Atwood refrigerator clear the AC No Supply error?
A simple reset will not permanently clear this error because the control board actively monitors for AC supply voltage at J9 and J11. If the underlying cause is not corrected, the alert will return immediately after power is restored. The error will only clear once a valid 120VAC supply is detected at those terminals or the operating mode is changed to match an available power source.
How much does it cost to repair the AC No Supply error on an Atwood refrigerator?
Repair costs vary widely depending on the root cause. If only a tripped breaker needs to be reset or a mode setting corrected, there is no parts cost and minimal labor. Wiring repairs or connector replacements at J9 or J11 are generally low cost, typically in the range of $20 to $80 for parts. A damaged power cord or AC inlet receptacle replacement can range from $30 to $120 in parts, with additional labor if a technician is required.

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