How do you replace heater core Ford Festiva?

To replace the heater core in a Ford Festiva, start by disconnecting the negative battery terminal and draining the coolant. Remove the dashboard and the center console to access the heater core, which is typically located behind the firewall. Disconnect the hoses and any electrical connections, then unbolt and remove the old heater core. Install the new heater core by reversing the process, ensuring all connections are secure before refilling the coolant and reassembling the dashboard.