Goodman furnace model#GCH90904CXAB the red light

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

Witch blower is running, the inducer or the systems blower?
System blower could mean the the high limit is opening and shutting down the systems gas train, I would check this out first.

The other problem could be with the pressure switch for the gas train, it is supplied from the inducer motor, check to see if it is operating fully.

HSI boards do go from time to time, this sounds more like a system control problem.

Voltage polarity switch.

When the light is blinking six times rapidly, this means the power volt polarity has gotten switched.

How to Troubleshoot a Goodman Furnace With Six Flashes

Videos as well

https://www.google.com/search?q=goodman+furnace+red+light+blinking+6+times

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There should be a chart pasted to the inside of the front access panel of the furnace. It will tell us what that particular blinking sequence means. Goodman isn't listing a gmp125-4 furnace so I need to assume it is a condensing gas furnace. I water has backed up into the draft inducing fan, the furnace will shut down. There is no reason for water dripping from the drain pan unless your A/C is running and the drain on the pan is plugged. Give me all the info. you can and exactly what is happening. Please look up the coded problem for me. I'll watch for your reply. I hope this is not too late to help.

Gas regulator or flame sensor for all GMT models

A volt/ohmmeter is only $3 at a place like Harbor Freight. Goodmans are known for overheating. Often the overheat switch is a one shot item that needs to be replaced every time it throws.
Think if it more like a fuse that melts.

You have a loose draft inducer fan hose to pressure switch

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The goodman furnace will try and light three time before it faults out for safety reasons. Adjust the flame sensor so that it is closer to the flame or actually in the pilot flame. If the flame sensor is inside the pilot flame and still does not stay lit, your flame sensor is probably defective and should be replaced. You can get one at Ferguson's counter sales.

THE ROLL OUT SWITCH IS LOCATED IN THE BURNER COMPARTMENT MOST CAN BE RESET

A constant red light (not blinking) indicates that the thermostat is not calling for heat. Of course you know it is but just to be safe, jump out R and W on the board. If it continues to do the same as you indicated, replace the board.