Goodman Furnace Error Code 3: How to Fix It

Easy 15-30 minutes High Severity Verified June 2026
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Error Code
3
Brand
Goodman
Product Type
hvac
Severity
High
DIY Difficulty
Easy
Estimated Fix Time
15-30 minutes
Goodman furnace error code 3 means the limit switch has opened due to overheating. This safety device shuts down the furnace to prevent damage or fire. Common causes include a dirty air filter, blocked vents, or a malfunctioning blower motor.
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Tools You'll Need

How to Fix Error Code 3

  1. Turn Off Power and Check Air Filter

    Always disconnect power before opening the furnace.

  2. Inspect Supply and Return Vents

  3. Reset the Furnace

  4. Test the Limit Switch

    Only test with power off. Ensure the furnace is cool to avoid burns.

  5. Check the Blower Motor

    Wear gloves and safety glasses when cleaning the blower.

  6. Inspect the Heat Exchanger

    A cracked heat exchanger can leak carbon monoxide. If suspected, call a professional immediately.

Parts You May Need

Limit switch
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Air filter
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Blower motor
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Limit switch
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Air filter
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Blower motor
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Limit switch
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Air filter
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Blower motor
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Limit switch
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Air filter
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Blower motor
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When to Call a Professional

If the error persists after checking airflow, replacing the filter, and resetting the furnace, or if you suspect a cracked heat exchanger or faulty blower motor, call a licensed HVAC technician.

Frequently Asked Questions

How do I reset my Goodman furnace after error code 3?
Turn off the thermostat and furnace power for 30 seconds, then turn it back on. The furnace should reset automatically once the limit switch closes.
Can a dirty air filter cause error code 3?
Yes, a dirty air filter restricts airflow, causing the heat exchanger to overheat and trip the limit switch. Replace the filter regularly.
Is error code 3 dangerous?
It indicates overheating, which can be a fire risk. Address it promptly. If a cracked heat exchanger is involved, carbon monoxide poisoning is possible.

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