Light flashes 4 times

You didn't provide very much information, but I will try to help you. Here are some possibilities.

1. The pressure switch may not be closing, or is stuck closed all the time.

2. If this furnace has a hot surface ignitor, it may be faulty or not getting voltage.

3. If this furnace has spark ignition, the module could be faulty or the ignitor may not be positioned correctly.

4. The gas valve may be faulty, turned off, or may not have gas pressure to the valve.

There may be other issues, but I tried to cover the most likely causes. I hope this helps!

Usually when your flame sensor gets dirty, the igniter and burner come on for approx.15 seconds, then shuts down. After 3 tries it will lock the furnace out. You have to shut the power off to the furnace then turn it back on to reset it. You need to turn all the power off to the furnace and remove the flame sensor, clean it with some very fine steel wool and put it back in. Be careful not to handle the Sensor (metal) part with your fingers. Turn the power on and set your thermostat so that it will call for Heat. That should fix, it if not you may need a new flame sensor.

IF YOU LOST POWER WHEN FURNACE WAS RUNNING IT TRIPPED ROLLOUT SWITCHES AND POSSIBLY THE HIGH LIMIT . IN CENTER OF ROLLOUT SWITCHES IS A LITTLE RED BUTTON THAT YOU RESET . YOU CAN ALSO TRY FINDING HIGH LIMIT WITH POWER SHUT OFF TO FURNACE PULL BOTH WIRES OFF HIGH LIMIT AND USE PAPER CLIP TO JUMP BETWEEN THE TWO WIRES MAKE SURE YOU DONT SHORT OUT AGAINST ANY METAL WHEN YOU TURN BACK ON IF IT WORKS YOU NEED A NEW HIGH LIMIT SWITCH.

https://www.repairclinic.com/RepairHelp/How-To-Fix-A-Furnace/171-377-1442688-/Goodman-Furnace-not-heating-GDS80703AXBC
Check out this site. Has DIY videos that cover your issue.

Problem: Your furnace will not ignite the gas to produce heat for your home. When a furnace has a bad ignitor what I see most of the time is the following sequence of operation:

1. Thermostat calls for heat. 2. Draft inducer motor starts. 3. Pressure switch attached by a small plastic or rubber tube senses the negative pressure produced by the draft inducer and closes. 4. Draft inducer runs for 30 seconds to a minute before you hear a gas hissing sound. The ignitor did not glow, the flame sensor (a small metal probe about 1/8" in diameter, with a white porcelain base) does not sense the flame, so after 8 to 10 seconds the hissing sounds stops with no ignition of gas to heat your home. Your furnace shuts down and goes into a lock out condition until you turn your power switch back off and on again. Then the sequence starts all over again with no ignition of the gas. Solution:You probably need to purchase and install a new ignitor. I would suggest that you inspect your ignitor closely for cracks. Make sure you do not touch the ignitor with your bare hands. If you do not visually see a crack, then you could have a furnace control board problem or a limit, rollout switch problem. The furnace's control board might not be supplying the voltage to the ignitor.If your furnace lights and the gas stays on for 8 to 10 seconds, then shuts right back off, then you need to clean your flame sensor with light sand paper or steel wool. You might need a new flame sensor, but most of the time they can be cleaned an will work well after cleaning.

Normally blower should run first and then only furnace will work. check with blower contactor.

Problem: Your furnace will not ignite the gas to produce heat for your home. When a furnace has a bad ignitor what I see most of the time is the following sequence of operation:

1. Thermostat calls for heat. 2. Draft inducer motor starts. 3. Pressure switch attached by a small plastic or rubber tube senses the negative pressure produced by the draft inducer and closes. 4. Draft inducer runs for 30 seconds to a minute before you hear a gas hissing sound. The ignitor did not glow, the flame sensor (a small metal probe about 1/8" in diameter, with a white porcelain base) does not sense the flame, so after 8 to 10 seconds the hissing sounds stops with no ignition of gas to heat your home. Your furnace shuts down and goes into a lock out condition until you turn your power switch back off and on again. Then the sequence starts all over again with no ignition of the gas. Solution: You probably need to purchase and install a new ignitor. I would suggest that you inspect your ignitor closely for cracks. Make sure you do not touch the ignitor with your bare hands. If you do not visually see a crack, then you could have a furnace control board problem or a limit, rollout switch problem. The furnace's control board might not be supplying the voltage to the ignitor. If your furnace lights and the gas stays on for 8 to 10 seconds, then shuts right back off, then you need to clean your flame sensor with light sand paper or steel wool. You might need a new flame sensor, but most of the time they can be cleaned an will work well after cleaning.

could be the thermostat sticking of the fan control afc not working sticking off on shut down thermostat sounds more like it

having a problem with a weather maker 8000. It will not come on at all unless I shut down the switch on the side of the furnace. filters is clean. it will start to light then stop

COULD POSSIBLY BE A BAD IGNIGHTER.I DON'T KNOW THIS SYTEM BUT THE SAFTY PROTOCALS ARE WORKING.THE THERMOCOUPLE(IT DETECTS HEAT)IS TELLING THE BOARD IT HAS NO IGNITION,THEREFORE KEEPING YOU FROM BLOWING YOUR HOUSE UP.IF IGNITION HAS'NT HAPPENED WITHIN A FEW SECONDS IT SHUTS THE GAS OFF.IF YOU DON'T KNOW WHAT YOUR DOING DON'T MESS WITH IT,.IF YOU GET INTO THE WRONG THING YOU WILL ALLOW NATURAL GAS OR PROPANE TO LEAK INTO YOUR HOME(THIS IS A BAD THING)THE COTROL BOARD BLINKING IS A TROUBLE CODE.USE YOUR OWN JUDGEMENT.IF YOU NEED FURTHER HELP CONTACT ME.THE IGNIGHTER IS EASY TO CHANGE.ENOUGH SAID!!!!!