Housing Assembly HVAC: Service and Repair

The Heater-A/C housing assembly must be removed from the vehicle and the two halves of the housing separated for service access of the heater core, evaporator coil, blend-air door, and each of the various mode control doors.

WARNING: ON VEHICLES EQUIPPED WITH AIRBAGS, REFER TO AIR BAGS AND SEAT BELTS/AIR BAGS BEFORE ATTEMPTING ANY STEERING WHEEL, STEERING COLUMN, OR INSTRUMENT PANEL COMPONENT DIAGNOSIS OR SERVICE. FAILURE TO TAKE THE PROPER PRECAUTIONS COULD RESULT IN ACCIDENTAL AIRBAG DEPLOYMENT AND POSSIBLE PERSONAL INJURY.

REMOVAL
1. Disconnect and isolate the battery negative cable.
2. Remove the instrument panel from the vehicle. Refer to: Body and Frame, Interior Trim, Dashboard/Instrument Panel, Service and Repair, Instrument Panel Service Procedures, Instrument Panel Assembly Replacement, Instrument Panel Assembly

3. If the vehicle is not equipped with air conditioning, go to Step 6. If the vehicle is equipped with air conditioning, recover the refrigerant from the refrigerant system.
4. Disconnect the liquid line refrigerant line fitting from the evaporator inlet tube. Install plugs in, or tape over all of the opened refrigerant line fittings.
5. Disconnect the accumulator inlet tube refrigerant line fitting from the evaporator outlet tube. Install plugs in, or tape over all of the opened refrigerant line fittings.
6. Drain the engine cooling system.
7. Disconnect the heater hoses from the heater core tubes. Install plugs in, or tape over the opened heater core tubes.
8. Unplug the heater-A/C system vacuum supply line connector from the tee fitting near the heater core tubes.

Heater-A/C Housing Remove/Install:

9. Remove the five nuts from the heater-A/C housing mounting studs on the engine compartment side of the dash panel. If necessary, loosen the battery hold-downs and reposition the battery for additional access.
10. Remove the cowl plenum drain tube from the heater-A/C housing mounting stud on the dash panel directly behind the engine cylinder head.
11. Remove the floor duct from the bottom of the heater-A/C housing.
12. Remove the one screw that secures the heater-A/C housing to the plenum bracket on the passenger compartment side of the dash panel.
13. Pull the heater-A/C housing down far enough to clear the defrost(demist and fresh air ducts, and rearward far enough for the mounting studs and the evaporator condensate drain tube to clear the dash panel holes.
14. Remove the heater-A/C housing from the vehicle.

Disassembly
1. Remove the heater-A/C housing from the vehicle and place it on a work bench.
2. Unplug the vacuum harness connectors from the floor door actuator and, if the unit is so equipped, the recirculation air door actuator.
3. Disengage the vacuum harness from any routing clips located on the lower half of the heater-A/C housing.
4. Disengage the heater-A/C wire harness connector and the blower motor relay wire harness connector push-in retainers from their mounting holes on the heater-A/C housing.
5. Remove the blower motor and blower wheel unit from the heater-A/C housing.
6. Carefully remove the foam seal from the flange around the blower motor opening in the heater-A/C housing. If the seal is deformed or damaged, it must be replaced.

Heater-A/C Housing Disassembly:

7. Pull the vacuum supply line and connector through the foam seal on the heater core and evaporator coil tube mounting flange of the heater-A/C housing.
8. If the unit is equipped with air conditioning, remove the screw that secures the clamp to the evaporator coil tubes and remove the clamp.
9. Carefully remove the foam seal from the heater core and evaporator coil tube mounting flange of the heater-A/C housing. If the seal is deformed or damaged, it must be replaced.
10. Use a screwdriver to pry off the two snap clips that help secure the upper and lower heater-A/C housing halves to each other.
11. Remove the 14 screws that secure the upper and lower heater-A/C housing halves to each other.
12. Carefully separate the upper heater-A/C housing half from the lower half

Assembly
1. Assemble the upper heater-A/C housing half to the lower half. During assembly, be certain of the following:

Heater-A/C Housing Assembly:

a. That each of the mode door pivot shaft ends is properly engaged in its pivot hole.
b. That the blower motor venturi ring is properly indexed and installed.
c. If the unit is equipped with air conditioning, that the evaporator coil tube rubber seal is properly positioned in the grooves in both the upper and lower heater-A/C housing halves.
2. Install the 14 screws and two snap clips that secure the upper and lower heater-A/C housing halves to each other. Tighten the screws to 2.2 Nm (20 in. lbs.).
3. Install the blower motor and wheel unit in the heater-A/C housing. See Blower Motor for the procedures.
4. Install the foam seals on the flanges around the blower motor opening and the heater core and evaporator coil tube mounting flange of the heater- A/C housing.
5. Insert the vacuum supply line and connector through the foam seal on the heater core and evaporator coil tube mounting flange of the heater-A/C housing.
6. If the unit is equipped with air conditioning, reinstall the evaporator coil tube clamp. Tighten the mounting screw to 2.2 Nm (20 in. lbs.).
7. Engage the heater-A/C wire harness connector and blower motor relay wire harness connector push-in retainers with their mounting holes in the heater-A/C housing.
8. Engage the vacuum harness to the routing clips and plug in the vacuum harness connector at the floor door actuator and, if the unit is so equipped, at the recirculation air door actuator.
9. Install the heater-A/C housing in the vehicle.

INSTALLATION
1. Position the heater-A/C housing to the dash panel. Be certain that the evaporator condensate drain tube and the housing mounting studs are inserted into their correct mounting holes, and that the openings on the top of the housing are properly aligned with the fresh air duct and defrost/demist duct.
2. Install and tighten the one screw that secures the heater-A/C housing to the plenum bracket on the passenger compartment side of the dash panel. Tighten the screw to 3.4 Nm (30 in. lbs.).
3. Install the floor duct to the bottom of the heater-A/C housing. See Floor Duct for the procedures.
4. Install the cowl drain tube onto the heater-A/C housing mounting stud on the dash panel directly behind the engine cylinder head.
5. Install and tighten the five nuts onto the heater-A/C housing mounting studs on the engine compartment side of the dash panel. Tighten the nuts to 6.2 Nm (55 in. lbs.).
6. If the battery was repositioned during the removal procedure, position the battery and tighten the hold-downs.
7. Connect the heater-A/C system vacuum supply line connector to the tee fitting near the heater core tubes.
8. Unplug or remove the tape from the heater core tubes. Connect the heater hoses to the heater core tubes and fill the engine cooling system.
9. If the vehicle is not equipped with air conditioning, go to Step 13. If the vehicle is equipped with air conditioning, unplug or remove the tape from the accumulator inlet tube and the evaporator outlet tube fittings. Connect the accumulator inlet tube coupler to the evaporator outlet tube. See Refrigerant Line Coupler for the procedures.
10. Unplug or remove the tape from the liquid line and the evaporator inlet tube fittings. Connect the liquid line coupler to the evaporator inlet tube.
11. Evacuate the refrigerant system.
12. Charge the refrigerant system.
13. Install the instrument panel in the vehicle. Refer to: Body and Frame, Interior Trim, Dashboard/Instrument Panel, Service and Repair, Instrument Panel Service Procedures, Instrument Panel Assembly Replacement, Instrument Panel Assembly

14. Connect the battery negative cable.
15. Start the engine and check for proper operation of the heating and air conditioning systems.