Where is the furnace filter located on the furnace of a Goodman Furnace?

https://hvac-boss.com/troubleshooting/goodman-furnace-error-codes/

According to this page, you can usually fix this 4 blink diagnosed problem by changing the air filter or tightening wiring (which it has a cautionary warning about tightening such too much) and checking the flue for blockage. The furnace has activated the primary open limit circuit.

Here is a troubleshooting page about the Goodman just blowing cold air: https://temperaturemaster.com/goodman-furnace-troubleshooting/#Goodman_Furnace_Blowing_Cold_Air

Poor air flow in the Goodman caused by blockages can result in the tripping of the rollover switches which would cause it to blow cold air. That is a safety measure. You don't want gas furnaces burning with insufficient air. Think carbon monoxide. Besides the air filter, the flame sensor or the burner could be dirty. The idea of trying to DYI that cleaning job is rather off putting. I hope changing the filter would work.

I trust it is not a fuse in the pilot flame sensor circuit blown. A repairman has the voltage testers for checking the electronics involved.

I can empathize with this. My furnace, another brand, went out recently. The repair man didn't know why it went out but simply adjusted a handle controlling gas flow to a position slightly different from what was recommended and it worked. All for $200.

https://www.repairclinic.com/RepairHelp/Furnace-Repair/36-377--/Goodman-Furnace-Troubleshooting

https://www.youtube.com/watch?v=zO1jKqwXu8s

https://www.goodmanmfg.com/products/gas-furnaces

The model number you listed is for the outside unit which does not have a filter. The indoor part of this system (the furnace or air handler) is what has the air filter. The size varies because the installer usually makes a bracket to hold the filter when the furnace is installed. Need to locate the filter and replace it with the same one. Size should be marked on the old filter.

Typically the filter is located externally of the furnace. If not the lower door near the blower housing. Turn off the power to the furnace 1st. and open that door to look for the filter

Translate four LED flashes to mean your furnace has a primary limit circuit open, possibly from loose wiring or blocked filters. Check and clean filters, tighten wiring and check the flue for blockages.
A typical limit looks like this: Consult your furnace schematic to determine how many of these puppy's are wired in and around the furnace. Make sure they all have continuity. Have the power OFF before you reset the limit. Ouch!

Somewhere in your furnace all of these flashes have a chart you can consult usually located on the backside of the blower cover.

If you need further help, reach me via phone at https://www.6ya.com/expert/dan_73bbd84fe1d95b61

Your filter will commonly be on the side of your furnace where the return air comes in, usually it will slide into a filter rack or you might have a small cover on it. When replacing a filter make sure the arrow on the filter is pointing in the direction of airflow, so the arrow should be pointing toward the furnace.

There is a switch on the blower compartment cover that needs to be closed to make your furnace work. It should be located on top frame of blower compartment, Make sure you have the cover properly closed. Hope this helps you. Thanks

Filters are usually added to the sheetmetal seperate from the furnace. All air must be filtered before entering the furnace. Turn on heat and feel ductwork to determine which direction air flow goes, warm will be supply and room temp. will be return. Filter should be on return side of furnace. Some of them may be filter grilles located in a central reurn on older homes with only one return in a hallway or sometimes the correct ductwork is not installed and they are inside the bottom panel where return ducts connect

It should be in the return air duct. The place the air is removed from the building on its way to the furnace.

look in and around where the blower motor is located. there has to be a filter compartment there. probably near the bottom as it looks like an upflow heater. make sure the filter door is closed. it may have a door interlock switch that cuts the burner out if it is not fully closed.

I don't know where you are located, but there is a Goodman distributor in Sacramento, CA. Also in Ontario CA. They are a distributor so they may be able to help you or tell where to find someone who will help. Goodman is also known as GMC or Janitrol.