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Part 2 – HVAC sub assembly removal and installation
The HVAC 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 door(s), and each of the various mode doors.
WARNING: ON VEHICLES EQUIPPED WITH AIRBAGS, DISABLE THE AIRBAG SYSTEM BEFORE ATTEMPTING ANY STEERING WHEEL, STEERING COLUMN, OR INSTRUMENT PANEL COMPONENT DIAGNOSIS OR SERVICE. DISCONNECT AND ISOLATE THE BATTERY NEGATIVE (GROUND) CABLE, THEN WAIT TWO MINUTES FOR THE AIRBAG SYSTEM CAPACITOR TO DISCHARGE BEFORE PERFORMING FURTHER DIAGNOSIS OR SERVICE. THIS IS THE ONLY SURE WAY TO DISABLE THE AIRBAG SYSTEM. FAILURE TO TAKE THE PROPER PRECAUTIONS COULD RESULT IN AN ACCIDENTAL AIRBAG DEPLOYMENT AND POSSIBLE PERSONAL INJURY.
1. Disconnect and isolate the battery negative cable.
2. Remove the instrument panel from the vehicle (see Part 1 – Instrument panel removal)
3. Recover the refrigerant from the refrigerant system.
4. Disconnect the liquid line refrigerant line from the evaporator inlet tube. Install plugs in, or tape over all of the opened refrigerant line fittings.
5. Disconnect the suction line refrigerant line from the evaporator outlet tube. Install plugs in, or tape over all of the opened refrigerant line fittings.
6. Disconnect the heater hoses from the heater core tubes. Clamp off the heater hoses to prevent loss of coolant. Refer to Cooling for the procedures. Install plugs in, or tape over the opened heater core tubes.
7. Remove the bolt from the HVAC housing mounting stud on the engine compartment side of the dash panel (Fig. 9).
8. Remove the rear floor heat ducts from the floor heat duct outlets (Fig. 10).
9. Remove the HVAC housing mounting nuts from the studs on the passenger compartment side of the dash panel (Fig. 11).
10. Remove the HVAC housing from the vehicle, ensuring that the interior is covered in case of loss of fluids.
DISASSEMBLY
1. Place the HVAC housing with the tubing side down on a work bench, making allowance for leakage of fluids.
2. Using a sharp knife, split the foam seal surrounding the panel outlet opening, at the dividing line of the upper and lower cases (Fig. 12).
3. Place the HVAC housing in the upright position on the work bench.
4. Remove the mode door actuator on the left side of the housing, which controls the mode door in the top of the case (Fig. 13) (Fig. 14).
5. Remove the screw with plastic washer holding the lever assembly to the upper case section, and move aside (Fig. 15).
6. Remove the 5 clips that secure the two housing halves to each other. There are 2 on either side at the center, and 1 located at the forward end of the mode door side of the case (Fig. 16).
7. Release the wire harness electrical connector(s) from the mounts on the lower case at the blower motor end of the unit (Fig. 17).
8. Remove the 10 screws that secure the two housing halves to each other.
9. Separate the top half of the HVAC housing from the bottom half (Fig. 18).
NOTE: The blend door sub-assembly is attached to the housing with 2 screws, and may be removed for service (Fig. 19).
ASSEMBLY
1. Place the top half of the HVAC housing on the bottom half. Be certain that each of the door pivot pins align with the pivot holes in the HVAC housing.
2. Install the 10 screws that secure the two housing halves to each other. Tighten the HVAC housing screws to 2.2 N·m (20 in. lbs.).
3. Attach the wire harness electrical connector(s) to the mounts on the lower case at the blower motor end of the unit.
4. Install the 5 clips that secure the two housing halves to each other. Check doors for binding after replacement, and after assembly of housing.
5. Install the screw with plastic washer holding the lever assembly to the upper case section.
6. Install the mode door actuator on the left side of the housing.
INSTALLATION
WARNING: REVIEW THE WARNINGS AND CAUTIONS IN PLUMBING BEFORE PERFORMING THE FOLLOWING OPERATION.
Any kinks or sharp bends in the refrigerant plumbing will reduce the capacity of the entire air conditioning system. Kinks and sharp bends reduce the flow of refrigerant in the system. A good rule for the flexible hose refrigerant lines is to keep the radius of all bends at least ten times the diameter of the hose. In addition, the flexible hose refrigerant lines should be routed so they are at least 80 millimeters (3 inches) from the exhaust manifold.
High pressures are produced in the refrigerant system when the air conditioning compressor is operating. Extreme care must be exercised to make sure that each of the refrigerant system connections is pressure-tight and leak free. It is a good practice to inspect all flexible hose refrigerant lines at least once a year to make sure they are in good condition and properly routed.
1. Position the HVAC 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.
2. Install the HVAC housing mounting nuts to the studs on the passenger compartment side of the dash panel. Tighten the nuts to 4.5 N·m (40 in. lbs.).
3. Connect the HVAC housing wire harness connectors.
4. Reinstall the rear floor heat ducts to the center floor heat duct outlets.
5. Install and tighten the bolt onto the HVAC housing mounting stud on the engine compartment side of the dash panel. Tighten the nuts to 7 N·m (60 in. lbs.).
6. Unclamp/unplug the heater core hoses and tubes. Connect the heater hoses to the heater core tubes and fill the engine cooling system. Refer to Cooling for the procedures.
7. Unplug or remove the tape from the suction line and the evaporator outlet tube fittings. Connect the suction line to the evaporator outlet tube. Tighten retaining nut to 28 N·m (250 in. lbs.).
8. Evacuate the refrigerant system.
10. Charge the refrigerant system.
11. Install the instrument panel in the vehicle
12. Connect the battery negative cable.
13. Start the engine and check for proper operation of the heating and air conditioning systems.
BLEND DOOR REMOVAL
1. Remove evaporator from lower case to ease access to plastic door shaft bushing.
2. Pinch the retention tabs holding the blend door pivot shaft to the case. The 3 plastic tabs, located on the inside of the case, are part of the shaft retainer.
3. Remove door(s).
BLEND DOOR INSTALLATION
1. Install the blend door(s) by snapping the pivot shaft into the HVAC case.
2. Install the evaporator in the lower case.
3. Reassemble the HVAC housing and install in the vehicle.
NOTE: The blend door sub-assembly is attached to the housing with 2 screws, and may be removed for service (Fig. 19).
MODE DOOR REMOVAL
1. Pinch the retention tabs holding the panel outlet door pivot shaft to the case. The 3 plastic tabs, located on the inside of the case, are part of the shaft retainer (Fig. 21).
2. Using a trim stick or another suitable wide flat-bladed tool, gently pry the panel outlet door pivot shaft retainer from the pivot shaft.
3. Remove the panel outlet door from the HVAC housing.
REMOVAL – HEAT/DEFROST DOOR
1. Remove the evaporator, and styrofoam tray from the lower case.
2. Place the HVAC housing upside down on a work bench.
3. Unscrew and remove the 2 floor heat ducts.
4. Unsnap and remove the duct adapter from the bottom of the heat/defrost door sub-assembly (Fig. 22).
5. Gently pry the metal linkage from the heat/defrost door lever.
6. Remove the heat/defrost door sub-assembly, which is attached to the housing with 4 screws (Fig. 23).
7. Pinch the retention tabs holding the heat/defrost door pivot shaft lever to the case. The 3 plastic tabs, located on the inside of the case, are part of the shaft retainer.
8. Remove the heat/defrost door (Fig. 24).
REMOVAL – PANEL/DEFROST DOOR
1. Pinch the retention tabs holding the panel/defrost door pivot shaft to the case. The 3 plastic tabs, located on the inside of the case, are part of the shaft retainer (Fig. 25).
2. Using a trim stick or another suitable wide flat-bladed tool, gently pry the panel/defrost door pivot shaft retainer from the pivot shaft.
3. Remove the panel/defrost door from the HVAC housing.
INSTALLATION – PANEL/DEFROST DOOR
1. Snap the panel/defrost door pivot shaft retainer on the pivot shaft.
2. Attach the panel/defrost door pivot shaft to the HVAC case.
INSTALLATION – PANEL OUTLET DOOR
1. Snap the panel outlet door pivot shaft retainer on the pivot shaft.
2. Attach the panel outlet door pivot shaft to the HVAC case.
INSTALLATION – HEAT/DEFROST DOOR
1. Install the heat/defrost door by snapping the heat/defrost door pivot shaft into the HVAC case.
2. Install the heat/defrost door sub-assembly and tighten the mounting screws to 2.2 N·m (20 in. lbs.).
3. Attach the metal linkage to the heat/defrost door lever.
4. Snap the duct adapter to the bottom of the heat/defrost door sub-assembly.
5. Install the 2 floor heat ducts and tighten the mounting screws to 2.2 N·m (20 in. lbs.).
6. Install the evaporator, and styrofoam tray in the lower case.
RECIRCULATION DOOR REMOVAL
1. Place the HVAC housing right side up on the work bench.
2. Unplug the wire/vacuum connector from the recirculation door actuator.
3. Remove the 2 screws fastening the recirculation door sub-assembly to the main housing (Fig. 26).
4. Raise the front of the door sub-assembly while releasing the 2 tabs holding the rear to the main housing, and remove the recirculation door housing.
5. Remove the electric/vacuum actuator from the recirculation door sub-assembly and set aside.
6. Pinch the retention tabs holding the recirculation door pivot shaft to the case. The 3 plastic tabs, located on the inside of the case, are part of the shaft retainer.
7. Remove the recirculation door from the recirculation air door housing.
RECIRCULATION DOOR INSTALLATION
1. Install the recirculation door in the recirculation air door housing by snapping the pivot shaft retention tabs into the case.
2. Install the electric/vacuum actuator on the recirculation door sub-assembly. Check door for binding after replacement.
3. Install the recirculation door housing on the HVAC case and tighten the 2 screws to 2.2 N·m (20 in. lbs.).
4. Plug in the wire/vacuum connector to the recirculation door actuator.