Goodman furnace troubleshooting

HVAC Logo IconBy HVAC.comJuly 31, 2023

Got Goodman furnace problems? Check out these DIY Goodman furnace troubleshooting tips. They may save you the trouble and expense of calling a repair technician.

Goodman furnace isn’t turning on

If your Goodman furnace isn’t turning on, check your circuit breaker or fuse box first. You may need to reset the circuit or repair a blown fuse.

If that doesn’t fix the issue, try resetting the furnace. You can remove the front access panel to find and press the reset button. Refer to the owner’s manual if you need instructions on how to do this.

If these Goodman furnace troubleshooting tips don’t get your furnace running, consider calling an electrician before contacting an HVAC tech.

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Goodman furnace isn’t blowing hot air

First, check your thermostat if your Goodman furnace isn’t blowing hot air. It should be set to “auto” and “heat.” If it’s set to “on,” your fan will blow air constantly, even when it’s not actively heating. 

Next, check your air filter. You should change your furnace air filter regularly. Check out our instructions on how to do this yourself. You can pick up a new furnace filter for less than $20. They’re also available at stores like Walmart and Lowe’s. 

Open the access panel and give your burner a look. If it’s dusty or dirty, you can clean it by blowing canned air or wiping it with a damp, soft cloth. Always make sure you turn the furnace off before handling any internal parts. 

Finally, look at your flame sensor. If it’s dirty, it can be removed and cleaned with steel wool that has no detergents. However, our HVAC experts also recommend using a dollar bill for cleaning. It’s durable enough to be effective but less likely to break or damage the sensor. If the sensor is cracked or damaged, you’ll need an HVAC technician to repair the part.

Goodman troubleshooting guides

Goodman furnace is cycling irregularly

Furnace cycles typically last about 15 minutes. If your Goodman furnace is cycling irregularly, first check your air filter. If it’s full of dust or other contaminants, change it out for a new furnace filter.

Next, make sure the vents in your home are open. At least 75% of the vents should have open grates for your furnace to function properly. Check that they aren’t blocked by furniture, laundry piles, Amazon boxes, etc.

If that doesn’t solve the problem, check your furnace ventilation. Most furnaces have an exhaust flue leading out to the roof or an external wall of the home. Make sure it’s not blocked or clogged by things like a snow pile or bird’s nest.

Next, open the access panel to check your burner. If it’s dirty, you can clean it with canned air or a soft rag (always turn the furnace off first).

The flame sensor may also be dirty. If so, remove and scrub it with detergent-free steel wool. If it’s visibly broken, you’ll need a pro to replace the part.

Goodman furnace won’t turn off

If your Goodman furnace won’t turn off, the first thing to check is your thermostat. Ensure it’s set to “heat” and “auto” (not “on”). The temperature should be set around 72℉. If the temperature is set too high, it could cause this problem.

Your home may be allowing hot air from the furnace to escape. Check for drafts around windows and doors. The Environmental Protection Agency has some good tips for air sealing. Consider investing in draft stoppers and weatherstrip to keep hot air in.

Other causes of a constantly running furnace may be a faulty limit switch, a broken power control board, or a malfunctioning thermostat. These aren’t DIY issues. You’ll need to call in a pro.

In over your head? Get a furnace repair pro out to fix your system.

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Goodman furnace codes

Sometimes, your furnace may give you a clue about what’s wrong. Below is a list of common Goodman furnace codes and what they mean for you.

You can usually see the error light on your Goodman furnace through a small opening in the front cabinet. Write down the error code and share it with your furnace repair person. If you power off the furnace, the code will reset and may not be visible when the technician arrives.

Light statusWhat it meansDIY or not?
Solid onNo connection to thermostatCheck thermostat settings. Check power to thermostat. If that doesn’t help, call a pro.
Blinking on and offFurnace ignition failureTurn furnace off and back on. If that doesn’t help, call a pro.
Rapid blinkingPower supply polarity reversedCall a technician. This isn’t a DIY fix.
2 blinksBlower or pressure switch failureCheck if there’s been a short or blown fuse. If that doesn’t help, call a pro.
3 blinksPressure switch openCall a technician. This isn’t a DIY fix.
4 blinksPrimary limit switch openReplace air filter. Open vents. Ensure exhaust flue isn’t blocked. Check power supply. If that doesn’t help, call a pro.
5 blinksFlame present but no call for heatThere could be a gas leak. Turn the furnace off immediately and call a technician.
6 blinksReversed polarityCall a technician. This isn’t a DIY fix.
7 blinksLow flameCall a technician. This isn’t a DIY fix.
8 blinksIgniter circuit failureCall a technician. This isn’t a DIY fix.
9 blinksHigh state pressure switch openCheck for loose electrical connection at the switch. An electrician can help you do this. Inspect pressure hose for crimping. If that doesn’t help, call a pro.

Goodman furnace owner’s manual

We’ve provided links below to the owner’s manuals for Goodman’s current line of furnaces. These may provide more Goodman furnace troubleshooting ideas. They may also help you identify parts while you’re troubleshooting.

If you don’t see your model listed below, you can find product information here.

GC9C80GC9C96GC9S80GCEC80
GCEC96GCES80GCSS92GCVC8
GCVC80GCVC96GCVM97GDS8
GHS8GM9C96GM9S80GM9S80-U
GM9S96GM9S96-UGME8GMEC96
GMES80GMES80-UGMES92GMES96
GMES96-UGMS80GMSS92GMSS96
GMVC8GMVC80GMVM97GMVS80-U
GMVS96-U   

When to call a pro for Goodman furnace problems

If the Goodman furnace troubleshooting tips above don’t work, give a professional HVAC technician a call. You can also reach out for help if you’re uncomfortable trying to troubleshoot on your own.

Click below to schedule an appointment with a local furnace repair pro who can get your Goodman furnace working.

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