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M Oglesby
M Oglesby, HVAC Technician
Category: HVAC
Satisfied Customers: 2038
Experience:  Universally Certified HVACR Technician
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My Goodman furnace wont fire up. Furnace light is blinking 4 times

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My Goodman furnace light is blinking 4 times. It won't fire up. What's the skinny?

M Oglesby :

Hello I am here to assist you.

Is the blower motor fan running?

JACUSTOMER-5lsshckm- :

Yes, blower is running. Igniter is new

Furnace just runs igniter. Doesn't get hot normally. In the past when igniter has gone out it still tried firing and you could hear and smell gas as it was firing up. It doesn't do that now. It just runs constantly. Little red light on computer or brain whatever blinks 4 times at a time

M Oglesby :

Remove the furnace door panels and look on the back of them to find out what the 4 flash LED troubleshooting code is indicating.

JACUSTOMER-5lsshckm- :

Open limit switch. Wow I'm stupid

M Oglesby :

There are two kinds of limit switches

JACUSTOMER-5lsshckm- :

How do I find that

M Oglesby :

The first that we will try to locate is the Main Limit Switch.

We need to bypass it.

It is a rectangular or square looking device that has two wires attached to it. It is usually located inside the furnace cabinet and sits on the back panel wall just above the gas valve.

Locate it and let me know when you find it.

JACUSTOMER-5lsshckm- :

Got it

M Oglesby :

Remove the two wires from the Main Limit Switch and attach or jump them together very good. While attached, attempt to turn the heat on. Let me know if the heat comes on or not.

JACUSTOMER-5lsshckm- :

Yes it fired. Pulled that piece to go buy it and will it hurt to let it run like this? Freezing in here - 52 degrees

M Oglesby :

That means you need a new Main Limit switch. It is not recommended to run the furnace with the limit bypassed. It is too risky.

Pull the Main Limit Switch off and go and buy a new one.

JACUSTOMER-5lsshckm- :

How does it disconnect? I got it pulled out. 2 big black wires - no way to disconnect. Didn't want to break it

M Oglesby :

It is very easy. Should only be 2 screws that hold it.

JACUSTOMER-5lsshckm- :

Hey buddy this was very helpful.

M Oglesby :
Also make sure you change your filter.
Thank you
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