With A/C
1. Drain the coolant.
2. Remove the evaporator. Service and Repair
3. Remove the instrument panel. Service and Repair
4. Disconnect the left and right ducts from the housing and remove the two coolant hoses from the right side of the housing.
5. Plug the heater core and hose openings to prevent coolant from spilling.
6. Disconnect the harness connector from the fresh air blower and remove the mounting bolts and nuts that hold the housing assembly to the body.
7. Remove the fresh air/heater housing assembly.
8. Disassemble the housing assembly to replace the heater core.
NOTE: Installation is the reverse of removal. Replace any soft seals and fill the cooling system, recharge the A/C.