You have to pull the dash first then the heater core, this is really involved as the a/c charge has to be blown then recharged.
Removal & Installation
NOTE: Heater core may be accessible without removing A/C heater assembly. Drain engine coolant. Remove passenger's side door sill plate and kick panel. Pull
passenger's side of carpet back enough to access bolt at rear of heater case cover plate. If all heater case cover plate screws are accessible, begin procedure
at step 6). If removing evaporator core, start at beginning of procedure.
1. Disable air bag system. See AIR BAG SYSTEM SAFETY article in GENERAL INFORMATION. Remove glove box by squeezing sides together. Remove 2 instrument panel retaining bolts from glove box
opening. Remove center floor duct. Remove center support bolt.
2. On diesel models, remove Powertrain Control Module (PCM) and mounting tray. On all models, remove trim panels. Remove both kick panels. Remove blower motor cover and blower motor. See HEATER
SYSTEMS RWD TRUCKS & VANS EXCEPT TRACKER.
3. Remove driver's lower instrument panel cover and knee bolster. Lower steering column. Remove instrument panel left and right pivot bolts located at lower corners of instrument panel. Remove 3 screws from
defroster vent near windshield. Disconnect any connectors and tilt instrument panel back far enough to access heater case. Remove coolant recovery reservoir from engine compartment.
4. Drain engine coolant. Disconnect heater hoses at core. Disconnect inlet and outlet lines at evaporator core, and cap openings. Remove accumulator. Remove A/C heater assembly to firewall screws and bolts.
Remove A/C heater assembly from vehicle.
5. Remove 4 screws attaching evaporator case cover. Remove evaporator core from A/C heater assembly.
6. Remove 7 screws attaching heater case cover plate. Remove screws and bracket attaching heater core to A/C heater assembly. See Fig. 12. Remove heater core.
7. To install, reverse removal procedure. Torque fasteners to specification. See TORQUE SPECIFICATIONS. Replace any seals. Lubricate new "O" rings with clean refrigerant oil prior to installation. Add one
ounce of clean refrigerant oil to evaporator. Evacuate, charge, and leak test A/C system. Fill cooling system. Start engine and check for leaks.