How do you replace heater core on 1998 Infinity QX4?

To replace the heater core on a 1998 Infiniti QX4, first, disconnect the battery and drain the coolant. Remove the dashboard and the center console to access the heater core. Disconnect the heater core hoses from the firewall, and unbolt the heater core from its housing. Install the new heater core, reassemble the components, and refill the coolant before reconnecting the battery.