To remove the heater core, first discharge the AC system and disconnect the battery's negative cable. Drain the cooling system and disconnect the heater hoses, blower motor connector, and A/C hoses. Label and disconnect the electrical wires at the AC relay, 
Thermostat, and blower motor resistors. Cut the retaining strap holding the blower/evaporator housing to the heater core housing. Remove the housing nuts from the firewall and the evaporator drain tube. Remove the right kick panel and instrument panel support bolt. Pull out the right side of the dash and rotate the housing to disengage it from the dash panel. Remove the blower/evaporator housing and the heater core. To install, position the heater core in the housing and install the screws. Reinstall the remaining parts in reverse order, refill the cooling system, and have the AC system evacuated, recharged, and leak tested. Check for proper operation. For 1997 and later models, additional steps may be required.