Replacement of the heater core is a challenging task for home mechanics, so it's important to keep track of assemblies by taking notes and storing screws and other hardware in small, labeled plastic bags for reassembly. Begin by turning the heater control setting to HOT and draining the cooling system, saving the coolant if it is relatively new or in good condition. Disconnect the cable from the negative terminal of the battery, then adjust the steering column as far back and down as possible before removing the steering wheel. Next, remove the lower trim panel from the left side of the instrument panel, followed by the instrument cluster and the accelerator pedal. Peel back the carpet in the driver's footwell to expose the air duct leading to the back seat, then detach the steering column from the instrument panel and lower it into the footwell without separating the steering shaft from the coupling. Unhook the three springs securing the upper end of the rear air duct and remove the fitting at the upper end of the duct. Place plastic sheeting on the footwell floor, then pull the clips out of the heater hose fittings and unbolt the bracket to remove the heater core. Carefully pull the coolant tubes out of the heater core, remove the bracket bolts, and take the bracket off the heater core, separating it from the evaporator housing. Wipe any spilled coolant from the inside of the housing, and during installation, follow the reverse order of removal, ensuring to tighten the nuts or bolts to the specified torque when attaching the steering column to the support bracket. Finally, refill the cooling system, reconnect the battery, and run the engine to check for leaks and proper operation of the system.