Replacement of the heater core is a difficult procedure for the home mechanic, involving removal of the entire dashboard, console, and many wiring connectors. If you attempt it at home, keep track of the assemblies by taking notes and keeping screws and other hardware in small, marked plastic bags for reassembly. Have the air conditioning system evacuated by a properly-equipped shop. Disconnect the cable from the negative terminal of the battery. Drain the cooling system. Remove the wiper motor and linkage. Remove the strut tower reinforcement bar, if equipped. Remove the lower right side cowl panel. Disconnect the heater hoses from the pipes that protrude through the firewall. Disconnect the air conditioning lines from the expansion valve block at the firewall. Seal all open ends to prevent contamination. Remove the entire instrument panel assembly. Remove the steering column. Disconnect the condensate drain hose from the heater unit. Unbolt and remove the heating/cooling and steering units from the vehicle as one complete assembly. Remove the heater tubing grommet, support and cover from the heater tubes. Remove the left foot air duct. Slide the heater core from the case. Reinstall the heater core into the heater unit and replace the assembly in the reverse order of removal. Refill the cooling system. Reconnect the battery and perform the necessary re-learn procedures. Check for leaks and proper system operation. Check the operation of all electrical components of the steering column and dash. Have the air conditioning system recharged by the shop that discharged it.
