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HomeRepair HelpGibson Central A/C RepairGibson Central air conditioner won't turn off Repair

Gibson Central air conditioner won't turn off

When a Gibson central air conditioner won't turn off, a shorted contactor or a bad wall thermostat or thermostat wiring is the most likely cause, keeping a cooling signal on the yellow (Y) terminal even after the thermostat is set to Off. A shorted furnace control board or main control board can cause the same problem, though it is a less common cause, by continuing to send voltage to the outdoor condensing unit and making the air conditioner run constantly. A shorted control board can continue sending voltage to the outdoor condensing unit, making the central air run constantly even when the thermostat is set to Off. The main control board can cause the same problem and should be inspected for visible damage. Next, check the wall thermostat or thermostat wiring. A stuck contact between the common (C) and yellow (Y) thermostat wire terminals can keep the contactor energized and cause the air conditioner to run continuously. A shorted contactor is less common but can also keep the condensing unit powered. You can test a thermostat for continuity with a multimeter, but disconnect power first and follow proper electrical safety procedures. The contactor and other outdoor components involve 240V line voltage and are not a safe DIY repair unless you are qualified. Enter your Gibson model number to find the exact replacement control board, thermostat, or contactor for your central air conditioner. Replacing a control board or contactor may require a licensed HVAC technician, but no refrigerant work is needed for these diagnoses.

01 - Gibson Central Air Conditioner Control Board

If the furnace control board has a short, it may be providing continuous voltage to the central air condensing unit preventing it from turning off. Inspect the control board for any damage and replace if necessary.
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Common

02 - Gibson Central Air Conditioner Main Control Board

If the furnace's main control board has a short, it may be providing continuous voltage to the central air condensing unit preventing it from turning off. Inspect the control board for any damage and replace if necessary.
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Common

03 - Gibson Central Air Conditioner Wall Thermostat

The wall thermostat has electrical contacts that send signal voltage back to the control board and the condensing unit's contactor to run the central air system. If the contact that controls the contactor sticks closed, it will send continuous voltage to the contactor, causing the central air system to run continuously. To determine if the thermostat is defective, use a multi-meter to test it for continuity. If the wall thermostat shows continuity between the common (“C”) and yellow (“Y”) thermostat wire terminals when the thermostat is in the off position, the thermostat has failed and will need to be replaced.
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Common

04 - Gibson Central Air Conditioner Wifi Thermostat

The WiFi thermostat has electrical contacts that send signal voltage back to the control board and the condensing unit's contactor to run the central air system. If the contact that controls the contactor sticks closed, it will send continuous voltage to the contactor, causing the central air system to run continuously. To determine if the thermostat is defective, use a multi-meter to test it for continuity. If the WiFi thermostat shows continuity between the common (“C”) and yellow (“Y”) thermostat wire terminals when the thermostat is in the off position, the thermostat has failed and will need to be replaced.
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Common

05 - Gibson Central Air Conditioner Contactor

The furnace control board sends a low voltage signal to the contactor. When the contactor receives the signal from the control board, it closes the circuit, sending voltage to the condensing unit components. If the contactor has shorted, it can send continuous voltage to the condensing unit's components resulting in the central air system not turning off. To determine if the contactor is at fault, use a multimeter to test the contactor for a short. If the contactor has shorted, replace it.
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Less Common

Frequently Asked Questions

Why won't my Gibson central air conditioner turn off?
Can a thermostat cause my central air conditioner to run constantly?
How do I test the contactor if my AC won't shut off?
Should I replace the Gibson control board when the air conditioner won't turn off?
How do I find the correct Gibson AC part for this repair?

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