How do you change a heater core in 1994 ford aerostar XL?

To change the heater core in a 1994 Ford Aerostar XL, first, disconnect the negative battery cable and drain the coolant. Remove the dashboard and the heater assembly cover to access the heater core. Disconnect the hoses from the heater core, unbolt it from the housing, and replace it with the new core. Finally, reassemble the components in reverse order, refill the coolant, and reconnect the battery.