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Dan
Dan, Auto Technician
Category: Chevy
Satisfied Customers: 3490
Experience:  GM Mark of Excellence/ Service Guild Participant with 13 years experience, ASE Master Certified
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Remove & Install Heater Core in a 1999 Chevy S10 Blazer I have

Resolved Question:

Remove & Install Heater Core in a 1999 Chevy S10 Blazer I have already removed the dash and every thing in which I see but there still seems to be something holding the heater core. Something is not allowing it to come out . Could you send me some diagrams and instructions for this job
Submitted: 5 years ago.
Category: Chevy
Expert:  Dan replied 5 years ago.
Heater/Vent Module Replacement

Removal Procedure


    Object Number: 281206  Size: SH
    Click here for detailed picture of above image.
  1. Remove the instrument panel. Refer to Instrument Panel Carrier Replacement in Instrument Panel, Gauges and Console.
  2. Drain the engine coolant. Refer to Cooling System Draining and Filling in Engine Cooling.
  3. On vehicles with automatic climate control only, cut (1) the outer layer of the A/C evaporator and blower module in order to access the service access cover. Refer to Blower Motor and Fan Replacement .
  4. On vehicles with automatic climate control only, remove the service access cover mounting screws.
  5. On vehicles with automatic climate control only, remove the service access cover.
  6. On vehicles without automatic climate control, remove the blower motor resistor. Refer to Blower Motor Resistor Replacement .

    Important: Mark and use the same mounting bolt (located behind the A/C evaporator and blower module) for the heater assembly during the installation process. Other mounting bolts are longer and will obstruct the operation of the temperature door.

  7. Remove the heat/vent module mounting bolt through the blower motor resistor or service access cover opening.
    Object Number: 1595  Size: SH
    Click here for detailed picture of above image.
  8. On vehicles with A/C only, remove the right wheel house panel. Refer to Wheelhouse Panel Replacement in Body Front End.
  9. On vehicles with A/C only, raise and support vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
  10. On vehicles with A/C only, remove the front right tire. Refer to Tire and Wheel Removal and Installation in Tires and Wheels.
  11. On the Utility only, remove the A/C evaporator and blower module heat shield screws.
  12. On the Utility only, slide the A/C evaporator and blower module heat shield toward the front of the vehicle.
  13. Remove the 2 lower heat/vent module mounting nuts.
  14. On the Utility only, remove the A/C evaporator and blower module heat shield bracket.
  15. Remove the bottom right heat/vent module mounting bolt from inside the vehicle.

    Important: The heat/vent mounting stud has a flange on the inside and cannot be removed from under the hood. Stop turning the stud after the threads are off the heat/vent module.

  16. On the Utility only, while an assistant inside the vehicle pulls the bottom right corner of the heat/vent module approximately 1 inch back, remove the 2 heat/vent module mounting studs.
  17. On vehicles with A/C only, lower the vehicle.
    Object Number: 529580  Size: SH
    Click here for detailed picture of above image.
  18. On vehicles with a 2.2L engine only, remove the engine wiring harness bracket located at the rear of the intake manifold. Refer to Valve Rocker Arm Cover Replacement in Engine Mechanical - 2.2L.
  19. Remove the heat/vent module mounting bolt located at the lower left side of the heater core to heater hose connection.
  20. Remove the heat/vent module mounting nut located at the lower right side of the heater core to heater connection.

    Important: The heat/vent mounting stud has a flange on the inside and cannot be removed from under the hood. Stop turning the stud after the threads are off the heat/vent module.

  21. On the Utility only, loosen the heat/vent module mounting studs until the threads are free from the heat/vent module.
  22. Disconnect all of the electrical connectors from the heat/vent module.
  23. Disconnect all of the vacuum lines from the heater assembly.
  24. Disconnect the heater hoses from the heater core.
  25. Remove the heat/vent module from the vehicle.

Installation Procedure


    Object Number: 529580  Size: SH
    Click here for detailed picture of above image.
  1. If replacing the heat/vent module, transfer the components from the old heat/vent module as necessary.

    Important: Before installing the heat/vent module to the vehicle, ensure that the heat/vent module mounting studs are located in the proper positions.

  2. Install the heat/vent module to the vehicle.
  3. Connect the heater hoses to the heater core.
  4. Connect all of the vacuum lines to the heater assembly.
  5. Connect all of the electrical connectors to the heat/vent module.
  6. Install the bottom right heat/vent module mounting bolt from inside the vehicle approximately halfway into the threads.

    Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

  7. On the Utility only, install the heat/vent module mounting stud located at the lower right side of the heater core to heater hoses connection in the engine compartment.

    Tighten
    Tighten the heat/vent module mounting stud to 4.5 N·m (22 lb in).

  8. On vehicles with A/C only, raise the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
  9. On the Utility only, install the bottom right heat/vent mounting studs. Ask an assistant to pull the bottom right corner of the heat/vent module back from inside the vehicle.

    Tighten
    Tighten the heat/vent module mounting studs to 4.5 N·m (22 lb in).

  10. On the Utility only, install the A/C evaporator and blower module heat shield bracket.
  11. Install the heater/vent module mounting nuts.

     

    Tighten
    Tighten the heat/vent module mounting nuts to 4.5 N·m (22 lb in).

  12. On the Utility only, slide the A/C evaporator and blower module heat shield into the original position.
  13. On the Utility only, install the A/C evaporator and blower module heat shield screws.

    Tighten
    Tighten the A/C evaporator and blower module heat shield screws 2.2 N·m (19 lb in).


    Object Number: 1595  Size: SH
    Click here for detailed picture of above image.
  14. On vehicles with A/C only, install the right front tire. Refer to Tire and Wheel Removal and Installation in Tires and Wheels.
  15. On vehicles with A/C only, lower the vehicle.
  16. Install the bottom right heat/vent module mounting bolt from inside the vehicle.

    Tighten
    Tighten the heat/vent module mounting bolt to 4.5 N·m (22 lb in).

  17. On vehicles with A/C only, install the right wheel house panel. Refer to Wheelhouse Panel Replacement in Body Front End.
    Object Number: 529580  Size: SH
    Click here for detailed picture of above image.
  18. Install the heat/vent module mounting nut located at the lower right side of the heater core to heater connection.

    Tighten
    Tighten the heat/vent module mounting nut to 4.5 N·m (22 lb in).

  19. Install the heat/vent module mounting bolt located at the lower left side of the heater core to heater hose connection.

    Tighten
    Tighten the heat/vent module mounting bolt to 4.5 N·m (22 lb in).

  20. On vehicles with the 2.2L engine only, install the engine wiring harness bracket located at the rear of the intake manifold. Refer to Valve Rocker Arm Cover Replacement in Engine Mechanical - 2.2L.
    Object Number: 281206  Size: SH
    Click here for detailed picture of above image.

    Important: Mark and use the same mounting bolt (located behind the A/C evaporator and blower module) for the heater assembly during the installation process. Other mounting bolts are longer and will obstruct the operation of the temperature door.

  21. Install the heat/vent module mounting bolt through the blower motor resistor or service access cover opening.

    Tighten
    Tighten the heat/vent module mounting bolt to 4.5 N·m (22 lb in).

  22. On vehicles without automatic climate control, install the blower motor resistor. Refer to Blower Motor Resistor Replacement .
  23. On vehicles with automatic climate control only, install the service access cover.
  24. On vehicles with automatic climate control only, install the service access cover mounting screws.
  25. On vehicles with automatic climate control only, install the outer layer of the A/C evaporator and blower module. Refer to Blower Motor and Fan Replacement .
  26. Refill the engine coolant. Refer to Cooling System Draining and Filling in Engine Cooling.
  27. Install the instrument panel. Refer to Instrument Panel Carrier Replacement in Instrument Panel, Gauges and Console
  28. . Heater Core Replacement

    Removal Procedure

    1. Remove the heater/vent module. Refer to Heater/Vent Module Replacement .
      Object Number: 426946  Size: SH
      Click here for detailed picture of above image.
    2. Remove the heater core access cover screws.
    3. Remove the heater core access cover.
      Object Number: 426950  Size: SH
      Click here for detailed picture of above image.
    4. Remove the heater core from the heater/vent module.

    Installation Procedure


      Object Number: 426950  Size: SH
      Click here for detailed picture of above image.
    1. Install the heater core to the heater/vent module.
      Object Number: 426946  Size: SH
      Click here for detailed picture of above image.

      Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

    2. Install the heater core access cover.

      Tighten
      Tighten the heater core access cover screws to 1.9 N·m (17 lb in).

    3. Install the heater/vent module. Refer to Heater/Vent Module Replacement
    4. . Blower Motor Resistor Replacement

      Notice: Do not allow the metal coils of the blower resistor to become grounded to any metal surface. This may result in internal circuitry damage.

        Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

      1. Disconnect the negative battery cable.
      2. Remove the A/C control relay bracket with the relay.
      3. Remove the blower resistor harness.
      4. Remove the stud from the dash panel, if necessary.
      5. Remove the blower motor resistor mounting screw.
        Object Number: 281206  Size: SH
        Click here for detailed picture of above image.
      6. Utility only- Cut the access cover (1) from the case.

        Cut all four sides of the cover in order to remove the three attaching screws. Use a sharp utility knife in order to cut the case. Make the cuts straight and clean because you must reinstall the access cover and the access cover must be visible to the customer.

      7. Remove the blower resistor.

      Installation Procedure


        Object Number: 281206  Size: SH
        Click here for detailed picture of above image.
      1. Install the blower motor resistor.

        Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

      2. Install the blower motor resistor mounting screw.

        Tighten
        Tighten the screw to 1.9 N·m (17 lb in).

      3. Utility only- Apply a bead of black weather-strip adhesive over the cut-line areas (1).
      4. Utility only- Allow the adhesive to set for 15 minutes, or until the adhesive skins over.
      5. Install the stud to the dash panel, if necessary.
      6. Install the resistor harness.
      7. Install the A/C relay bracket into the body.
      8. Connect the negative battery cable.
Dan, Auto Technician
Category: Chevy
Satisfied Customers: 3490
Experience: GM Mark of Excellence/ Service Guild Participant with 13 years experience, ASE Master Certified
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