Heater Core: Service and Repair

REMOVAL

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.
- If the vehicle is equipped with Air Conditioning, review the warnings and cautions before performing the following operation. Service Precautions

Remove and disassemble the HVAC housing.
1. Disconnect and isolate the battery negative cable. Remove the instrument panel from the vehicle.
2. Remove the instrument panel from the vehicle. Service and Repair
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. Service and Repair
4. Disconnect the liquid line refrigerant line fitting from the evaporator inlet tube. Service and Repair
5. Disconnect the accumulator inlet tube refrigerant line fitting from the evaporator outlet tube. Service and Repair Install plugs in, or tape over all of the opened refrigerant line fittings.
6. Drain the engine cooling system. Service and Repair
7. Disconnect the heater hoses from the heater core tubes. Install plugs in, or tape over the opened heater core tubes.
8. Unplug the HVAC system vacuum supply line connector from the tee fitting near the heater core tubes.






9, Unplug the HVAC unit wire harness connector, which is fastened to the HVAC housing next to the blower motor relay (HVAC UNIT CONNECTOR).






10. Remove the five nuts from the HVAC housing mounting studs on the engine compartment side of the dash panel. Remove or reposition the evaporator canister for additional access, if required.
11 Pull the HVAC housing rearward far enough for the mounting studs and the evaporator condensate drain tube to clear the dash panel holes.
12. Remove the HVAC housing from the vehicle.

Fig.69 Heater Core Remove/Install:

13. Lift the heater core out of the lower half of the HVAC housing.

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






7. Pull the vacuum supply line and connector through the foam seal on the heater core and evaporator coil tube mounting flange of the HVAC housing (HVAC HOUSING DISASSEMBLY).
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 HVAC 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 HVAC housing halves together.
11. Remove the 14 screws that secure the upper and lower HVAC housing halves together.
12. Carefully separate the upper HVAC housing from the lower half.

ASSEMBLY
1. Assemble the upper HVAC housing half to the lower half. During assembly, be certain of the following.






a. That each of the mode door pivot shaft ends are properly engaged in tis 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 HVAC housing halves.
2. Install the 14 screws and two snap clips that secure the upper and lower HVAC housing halves to each other. Tighten the screws to 2.2 N�m (20 in. lbs.).
3. Install the blower motor and wheel unit in the HVAC housing. Service and Repair
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 HVAC 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 HVAC housing.
6. If the unit is equipped with air conditioning, reinstall the evaporator coil tube clamp. Tighten the mounting screw to 2.2 N�m (20 in. lbs.).
7. Engage the HVAC wire harness connector and the blower motor relay wire harness connector push in retainers with theirr mounting holes in the HVAC harness.
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.

INSTALLATION

WARNING: If the vehicle is equipped with Air Conditioning, review the warnings and cautions before performing the following operation. Service Precautions

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 and tighten the five nuts onto the HVAC housing mounting studs on the engine compartment side of the dash panel. Tighten the nuts to 6.2 N.m (55 in.lbs.).
3. If the evaporation canister was repositioned during the removal procedure, reinstall it to its proper position.
4. Connect the HVAC system vacuum supply line connector to the tee fitting near the heater core tubes.
5. 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.
6. If the vehicle is not equipped with air conditioning, go to Step 10.
7. 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. Service and Repair
8. Evacuate the refrigerant system. Service and Repair
9. Charge the refrigerant system. Service and Repair
10. Install the instrument panel in the vehicle. Service and Repair
11. Connect the battery negative cable.
12. Start the engine and check for proper operation of the heating and air conditioning systems.