I have a bryant 397h furnace and the blower will not turn off.I replaced the control center circuit board and still runs. Any suggestions?

Shorted thermostat wire. Label and remove the thermostat wires in the furnace. If the blower stops you have a short in the wiring or the thermostat. If not then it is in the furnace.

Does the system heat otherwise? If so, something may be wired wrong. If not, the primary limit control may be stuck open. Try tapping between the terminals with the butt of a screwdriver. If normal operation is restored, the system may be overheating for some reason.