Blower fan not working on heat or cool replaced motor furnace burner ignites trane furnace control board flashing no code board #cnt2789 white rodgers

Check for power to the blower when it should be running. If no power, you need a new control board. Did you replace the capacitor for the motor?

Yes I put new capacitor run jumper from door switch to hi fan speed and it ran

Do you know what board replaces cnt2789 is it 50a55-843

I honestly have no idea. Going to have to contact a supplier, or the manufacturer for that one. I wouldn't take any chances when it comes to board replacement, as if you get the wrong one, they may not take it back.