How do you change heater core for 2004 buick rainier?

To change the heater core in a 2004 Buick Rainier, first, disconnect the battery and drain the coolant. Remove the dashboard and the center console to access the heater core, which is typically located behind the glove compartment. Disconnect the heater core hoses and any electrical connections, then unmount and replace the old core with a new one. Reassemble the components in reverse order, refill the coolant, and check for leaks.