To remove the heater core, begin by discharging the air conditioning system if the vehicle is equipped with one. Turn the heater control setting too hot and drain the cooling system, saving the coolant if it's in good condition. Disconnect the cable from the negative battery terminal and disconnect the heater hoses from the firewall in the engine compartment. Remove the rubber grommets where the heater core tubes pass through the firewall. Proceed to remove the air conditioning expansion valve, the steering column, and the entire instrument panel. Disconnect the electrical connectors from the
Blower Motor and blower resistor, and remove the blower unit. Remove the rear floor duct, upper air duct, and defroster duct assembly. Take out the vertical instrument panel braces, instrument panel reinforcement beam, and remaining air conditioning unit fasteners. Disconnect the wiring harness along the blower motor housing, separate the blower motor housing from the air conditioning unit, and remove the quick heater from the housing. Finally, remove the retaining clamp and extract the heater core from the air conditioning unit housing. For installation, follow the reverse order of the removal steps. Reinstall the remaining parts, refill the cooling system, reconnect the battery, and run the engine while checking for leaks and proper system operation. If equipped, recharge the air conditioning system.