Bypassing a Furnace Control Board with a 90-340 Relay to get Blower Running 

This video saved a customer from the heat of Texas. Her motherboard burnt up and I had to bypass it. I had a 90-340 in the truck and I hooked it all up. She was cooling within the next hour. Get it done fellas, I never used on before.

I like that method. I usually straight wire the fan until I can get them a new board but your method allows for the fan to run with everything else like normal until you can get a new board.

So far this is the best video I have seen for peforming this temperary fix.

This is an amazing video, straight to the point, you made it look easy. Thank you so much!

I love your videos man, I've been working as maintenance tech for a couple of years and your content has helped me a lot.

You're a hell of a tech bro! I've never used a relay just a contactor or actually what I like to do it hook the fan speed up to the door switch....but good job. Now I know how to do it!

Great video!

Thanks for sharing and teaching

Oh mugid was about time someone did it so simple

Good job.

Just for future as long as you dont have an ecm fan motor you can take your heat wire off and put it on the EAC terminal which will also do the same thing without having to add a whole seperate relay because the eac is electric air cleaner which has its own relay to turn on when the furnace turns on.... ive done it multiple times till i get a new ifc board.... or you can unsolder the relay from the board and solder on a new one if u got it which most people wouldnt so just pull the wire off and put it on eac terminal which is a 120 terminal...... let me know if you have tried this before

I just need to know if i can use 90380 instead of that 90340. Its all i got and its the Weekend. I guess im gonna have to wait til Monday

Question. How are you able to work on hvac equipment and get supplies? I’m doing maintenance right now and they want me to work on some hvac equipment. The problem I’m running into is I can’t get into supply houses for equipment. What can I do to get into supply houses assuming your able to? Do you have a mechanical contractors liscence for hvac? I’m stuck on how to go about this

thanks for sharing. awesome work. Question: if you were to use the low speed (heating), where would you connect it to the relay?

Thank you

If you don't mind me asking, what do you record your videos with? Keep up the great work.

if you can find the relay that goes on the board that's a pretty easy board fix

How can bypass if is the heat?

You said that the board is bad so why still the natural works there? 🤔

In that application why not just use a spst 90290 or other rectangluar fan relay, the other circuits are not being utilized, and eliminates the thunk noise people will complain about

Bypass you dont use the board?

👍👍👍👍👍🔥🔥🔥🪛🪛🪛🪛🪛

I keep one of those relays on hand for an emergency situation just like in your case. I put it in place of the goodman AWUF blower board if I dont have a board on hand for some reason. Its funny how some guys are amazed when they see something like this done cuz all they know is swap out part for part. But if you understand how the system & the relays work you can make it happen. Nice job bro! 🛠️👍

Thanks