Carrier

[Ski5562]

Good morning,
I was recently called to diagnose an older Carrier furnace that was short cycling, I found the cause to be a dirty filter and replaced it. I checked everything else and performed maintenance on it and all seemed good to go.
I got a call back and the furnace is working but after it's satisfied on heating, the blower will disengage and immediately turn back on for a second, tested everything I felt might be the problem and all looks good but it's still happening.
Any suggestions on what it might be are appreciated.

[Admin]

It could be a "chattering" relay on the furnace control board.  If you disconnect the G wire from the furnace does this still happen?

If so I would look at replacing the control board, and explain to the client that likely a dirty filter caused the furnace to cycle on limit and that eventually wore out the old relay due to all the excessive starting and stopping.

[Ski5562]

Thank you, I will look into that