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Furnace Blinking Red Light

A blinking red LED on your furnace control board is a diagnostic code — the flash count or pattern maps to a specific fault. Find your brand below to decode the exact error and next steps.

Reviewed July 2026

What does furnace blinking red light mean?

Manufacturers use LED flash patterns instead of a numeric display on many furnaces. Count the flashes or note steady vs blinking, then match your brand to the correct code page. Meaning varies by brand — the same flash count can indicate different faults.

What usually causes furnace blinking red light?

Ignition or flame failuremost common

Typical repair: $150–$400

Limit or rollout switch tripcommon

Typical repair: $150–$600

Pressure switch faultcommon

Typical repair: $175–$550

Find your exact error code

Select your furnace brand to jump to the code page for this symptom.

Goodman1 FlashIgnition or flame-proving failureIntertherm4 BlinksLimit circuit openedLuxaire5 BlinksFlame-rollout safety lockoutCarrier14Ignition lockoutMiller4 BlinksLimit circuit opened

What should I check first when furnace blinking red light?

  1. Count the number of flashes or note the blink pattern.
  2. Select your furnace brand below to see the matching error code.
  3. Write down the code before resetting power.
  4. Replace the air filter if the code points to a limit or airflow fault.

What a repair costs

A furnace ignitor replacement typically costs between $150 and $400 nationally.

Typical repair cost
$150 – $400furnace ignitor replacement
Where the money goes
Part $25–$100Labor $50–$375Typical labor time: 0.5–1 hrs

This is general information, not professional advice. Gas, electrical, and combustion repairs can be dangerous — when in doubt, call a licensed technician.