Goodman Furnace Blinking a Red Light? How to Read the Code

That blinking light isn't random — it's the furnace telling you exactly what's wrong, in Morse-code-for-furnaces. Count the flashes and you know more than most callers ever tell the dispatcher.

Safety first, every page: if you smell gas anywhere in the house, stop — don't flip switches or reset anything. Leave and call your gas company from outside.

How to read it

Look through the small sight glass in the furnace's lower front panel. The light blinks a number of times, pauses, then repeats. That count is the code. Two more things before you do anything else:

• Write down the code AND your model number (on a sticker inside or near the upper panel). Cutting power clears the code, and a cleared code is a clue destroyed.
• The exact legend for YOUR furnace is printed on the inside of the front door panel. Codes below are the common ones across many Goodman models, but the door sticker outranks any website — including this one.

Common Goodman flash codes

• 1 flash — ignition failed several times and the furnace locked itself out. Often a dirty flame sensor or ignition issue. Many models retry on their own after an hour or two, or after a power cycle.
• 2 flashes — pressure switch stuck closed. Usually a pro call.
• 3 flashes — pressure switch open: the furnace can't confirm its vent is drawing. Check the white PVC vent pipes outside for snow, leaves, or nests blocking the openings — that one's free.
• 4 flashes — high limit tripped: the furnace overheated. The classic cause is a clogged filter or blocked vents. Check the filter first.
• 5 flashes — flame sensed when there shouldn't be one. Shut it off and call a pro.
• 7–9 flashes — blower motor trouble. Pro territory.
• Continuous fast blink — often reversed electrical polarity; common after electrical work or a generator hookup. Electrician or HVAC pro.
• Steady on — normal. No fault.

The two codes you can often clear yourself

A 3-flash cure can be as simple as clearing snow and debris from the outside vent pipes. A 4-flash cure is often a fresh filter and open vents, then 15 minutes of patience. After fixing the cause, reset by turning the furnace's power switch off for 30 seconds, then back on.

If the same code returns after one reset — stop resetting. Repeated resets against a real fault can turn a small repair into a big one.

Amana owners: same language

Amana and Goodman are the same family under the hood, and most Amana furnaces blink the same dialect. Same reading method, same door-sticker rule.

Call smart

The code plus your model number is exactly what a good shop wants to hear. The free troubleshooter asks for both, walks the free fixes first, and gives you a summary to read to the dispatcher.

Related symptoms

• Furnace won't turn on
• Furnace shuts off after a few seconds
• Furnace short cycling

Start the free troubleshooter → Free. No sign-up. Know before you call.

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