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GM_MASTER_DENNY
GM_MASTER_DENNY, GM and ASE Master Tech/Shop Foreman
Category: Chevy
Satisfied Customers: 178
Experience:  Over 15 years experience in automotive repair. GM Mark Of Excellence Winner for several years.
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I have a 98 s10 and the heat wont blow out on the floor. It

Resolved Question:

I have a 98 s10 and the heat won't blow out on the floor. It blows everywhere but the floor. When you put it on the floor it seems like it trys to send the air their but then it just starts coming out the defrost. Just wondering how to fix this. Thanks
Submitted: 5 years ago.
Category: Chevy
Expert:  GM_MASTER_DENNY replied 5 years ago.

Look under the dash on the driver side toward the center of the dash. You will see a couple of vacuum actuators mounted to the side of the HVAC case. Down at the bottom of the case, there is a linkage that connects to a white lever. Operate the heater mode control while observing the linkages. You will notice the white lever will wobble around. The lever is broken where it attaches to a door.When this happens, the floor vents will not open. You will have to remove the HVAC case to repair this. The parts cost about 30.00.

 

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Customer: replied 5 years ago.
i just checked to see if it's wobbling around and its not. i even tried to wiggle it around and it seems tight. it seems like it rotates like it should when i use the controlls. Do i have to take the whole dash apart to take the HVAC case out? or could it be something else? Thanks again Ted
Expert:  GM_MASTER_DENNY replied 5 years ago.
It is one of two things. There is no vacuum to the mode valve, or the floor vent door is damaged. Since the mode valve is moving the levers, the door must be damaged. It can be difficult to see sometimes. The lever is made to the door and the lver will break away from the door, but stay in place on the HVAC case. This will cause the lever to move but the door won't move. You might have to disassemble the linkages on the outside of the case in order to see where it's broken.
Customer: replied 5 years ago.
Do i have to take the whole dash apart? Because i'm trying to and i can't seem to get it out. I'v taken all the bolts and screews i can see out is their some sort of trick?
Expert:  GM_MASTER_DENNY replied 5 years ago.

Yes, the whole thing needs to come out. It is about a 7 to 8 hour job.

 

Heater/Vent Module Replacement

Removal Procedure


    Object Number: 617612  Size: SH
    Click here for detailed picture of above image.
  1. Remove the instrument panel. Refer to Instrument Panel Carrier Replacement in Instrument Panel, Gages 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 the outer layer of the A/C evaporator and blower module in order to access the service access cover.
    Object Number: 617623  Size: SH
    Click here for detailed picture of above image.
  4. On vehicles with automatic climate control only, remove the service access cover mounting screws (1).
  5. On vehicles with automatic climate control only, remove the service access cover (2).
  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 for the heater/vent module 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 2.5 mm (1 in) 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 2.2 L 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 - 2.2 L.
  19. Remove the HVAC module mounting bolt located at the lower left side of the heater core to heater hose connection.
  20. Remove the HVAC 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 HVAC module mounting studs until the threads are free from the heat/vent module.
  22. Disconnect all of the electrical connectors from the HVAC module.
  23. Disconnect all of the vacuum lines from the heater assembly.
  24. Disconnect the heater hoses from the heater core.
  25. Remove the HVAC module from the vehicle.

Installation Procedure


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

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

  2. Install the HVAC 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 HVAC module.
  6. Install the bottom right HVAC 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 HVAC module mounting stud located at the lower right side of the heater core to heater hoses connection in the engine compartment.

    Tighten
    Tighten the HVAC module mounting stud to 4.5 N·m (40 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 HVAC mounting studs. Ask an assistant to pull the bottom right corner of the HVAC module back from inside the vehicle.

    Tighten
    Tighten the heat/vent module mounting studs to 4.5 N·m (40 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 HVAC module mounting nuts to 4.5 N·m (40 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 HVAC module mounting bolt from inside the vehicle.

    Tighten
    Tighten the HVAC module mounting bolt to 4.5 N·m (40 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 HVAC module mounting nut located at the lower right side of the heater core to heater connection.

    Tighten
    Tighten the HVAC module mounting nut to 4.5 N·m (40 lb in).

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

    Tighten
    Tighten the HVAC module mounting bolt to 4.5 N·m (40 lb in).

  20. On vehicles with the 2.2 L 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 - 2.2 L.

    Important: Use the same mounting bolt marked during removal for the HVAC module during the installation process. Other mounting bolts are longer and will obstruct the operation of the temperature door.

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

    Tighten
    Tighten the HVAC module mounting bolt to 4.5 N·m (40 lb in).

  22. On vehicles without automatic climate control, install the blower motor resistor. Refer to Blower Motor Resistor Replacement .
    Object Number: 617623  Size: SH
    Click here for detailed picture of above image.
  23. On vehicles with automatic climate control only, install the service access cover (2).
  24. On vehicles with automatic climate control only, install the service access cover mounting screws (1).

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


    Object Number: 617612  Size: SH
    Click here for detailed picture of above image.
  25. On vehicles with automatic climate control only, install the outer layer of the A/C evaporator and blower module.

    Important: Do not use RTV. Apply the adhesive bead as straight as possible. Allow the adhesive to set for 15 minutes or until the adhesive becomes tacky.

  26. Seal the cut line using black weather-strip adhesive.
  27. Refill the engine coolant. Refer to Cooling System Draining and Filling in Engine Cooling.
  28. Install the instrument panel. Refer to Instrument Panel Carrier Replacement in Instrument Panel, Gages and Console.
  29. Calibrate the HVAC module actuator.

Instrument Panel Carrier Replacement

Removal Procedure

  1. On vehicles equipped with a manual transmission, remove the shift lever.
  2. On vehicles equipped with an automatic transmission, perform the following steps:
    2.1. Apply the park brake.
    2.2. Insert the ignition key and turn the ignition switch to the RUN position.
    2.3. Depress the brake pedal and shift the transmission to the 1 position.
    2.4. Turn the ignition switch to the OFF position.

    Object Number: 392686  Size: SH
    Click here for detailed picture of above image.

    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.

  3. Disconnect the battery negative cable.
  4. Remove the left sound insulator. Refer to Instrument Panel Insulator Panel Replacement - Left Side .
  5. Remove the right instrument panel sound insulator. Refer to Instrument Panel Insulator Panel Replacement - Right Side .
  6. If the vehicle is equipped with a multiple CD changer located in the center console, remove the center console. Refer to Front Floor Console Replacement .
  7. Remove the center sound insulator. Refer to Closeout/Insulator Panel Replacement - Center .
  8. Remove the lower left instrument panel mounting bolt.
  9. Remove and retain the instrument panel storage compartment. Refer to Instrument Panel Compartment Door Replacement .
  10. Remove the lower right instrument panel mounting bolt.
    Object Number: 392691  Size: SH
    Click here for detailed picture of above image.
  11. Remove and retain the left and right speakers and the speaker grilles. Refer to Radio Front Speaker Replacement in Entertainment.
  12. Use a flat-bladed tool in order to remove the windshield defroster grille. Retain the grille and sunload sensor for use on the next IP carrier.
    Object Number: 392690  Size: SH
    Click here for detailed picture of above image.
  13. If equipped with a sun load temperature sensor, twist the sensor ¼ turn counterclockwise in order to disengage.
  14. Disconnect the brown electrical connection from the body control module (BCM).
  15. Disconnect the purple electrical connection from the body control module (BCM).
  16. Remove the knee bolster. Refer to Knee Bolster Replacement .
  17. Remove and retain the instrument cluster. Refer to Instrument Cluster Replacement .
  18. Remove and retain the radio. Refer to Radio Replacement in Entertainment.
  19. Remove the HVAC control assembly. Refer to the appropriate procedure:
    Control Assembly Replacement in Heating and Ventilation (Non-A/C)
    Control Assembly Replacement in HVAC Systems with A/C - Manual
    Control Assembly Replacement in HVAC Systems with A/C - Automatic

    Caution: This vehicle is equipped with a Supplemental Inflatable Restraint (SIR) System. Failure to follow the correct procedure could cause the following conditions:

    Air bag deployment
    Personal injury
    Unnecessary SIR system repairs
    In order to avoid the above conditions, observe the following guidelines:
    Refer to SIR Component Views in order to determine if you are performing service on or near the SIR components or the SIR wiring.
    If you are performing service on or near the SIR components or the SIR wiring, disable the SIR system. Refer to Disabling the SIR System.

     

  20. Disable the passenger side SIR system. Refer to Disabling the SIR System in SIR.
    Object Number: 392681  Size: SH
    Click here for detailed picture of above image.
  21. Remove the left and right instrument panel driver knee bolster brackets.
  22. Lower the steering column for clearance. Refer to Steering Column Replacement in Steering Wheel and Column.
    Object Number: 303370  Size: SH
    Click here for detailed picture of above image.

    Important: Label all of the connections in order to avoid improper installation.

  23. Remove the top instrument panel screws.
  24. Roll the instrument panel down.
  25. Disconnect the electrical connections, as needed.
  26. Remove the fastener that retains the radio antenna cable to the instrument panel.
  27. Remove the instrument panel from the vehicle.

    If replacing the instrument panel carrier, retain the parts for assembly of the new instrument panel carrier.

Installation Procedure


    Object Number: 303370  Size: SH
    Click here for detailed picture of above image.
  1. Install the retained parts from the original instrument panel.
  2. Install the instrument panel to the vehicle.

    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.

  3. Install the fastener that retains the radio antenna cable to the instrument panel.

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

  4. Connect the electrical connectors, as needed.
  5. Roll the instrument panel up.
  6. Install the top instrument panel screws.

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


    Object Number: 392681  Size: SH
    Click here for detailed picture of above image.
  7. Raise the steering column into position. Refer to Steering Column Replacement in Steering Wheel and Column.
  8. Install the left and right instrument panel driver knee bolster brackets.

    Tighten
    Tighten the screws/bolts to 6.3 N·m (56 lb in).


    Object Number: 392690  Size: SH
    Click here for detailed picture of above image.
  9. Enable the passenger side SIR system. Refer to Enabling the SIR System in SIR.
  10. Install the HVAC control assembly to the instrument panel. Refer to the appropriate procedure:
    Control Assembly Replacement in Heating and Ventilation (Non-A/C)
    Control Assembly Replacement in HVAC Systems with A/C - Manual
    Control Assembly Replacement in HVAC Systems with A/C - Automatic
  11. Install the radio. Refer to Radio Replacement in Entertainment.
  12. Install the instrument cluster. Refer to Instrument Cluster Replacement .
  13. Install the knee bolster. Refer to Knee Bolster Replacement .
  14. Connect the purple electrical connection to the body control module (BCM).
  15. Connect the brown electrical connection to the body control module (BCM).
  16. If equipped with a sun load temperature sensor, install the sensor to the defroster grille by twisting the sensor ¼ turn clockwise.
    Object Number: 392691  Size: SH
    Click here for detailed picture of above image.
  17. Install the windshield defroster grille by pressing carefully pressing the grille into place.
  18. Install the left and right speakers and the speaker grilles. Refer to Radio Front Speaker Replacement in Entertainment.
    Object Number: 392686  Size: SH
    Click here for detailed picture of above image.
  19. Install the lower right instrument panel mounting bolt.

    Tighten
    Tighten the bolt to 11.5 N·m (102 lb in).

  20. Install the instrument panel storage compartment. Refer to Instrument Panel Compartment Door Replacement .
  21. Install the lower left instrument panel bolt.

    Tighten
    Tighten the bolt to 11.5 N·m (102 lb in).

  22. Install the center sound insulator. Refer to Closeout/Insulator Panel Replacement - Center .
  23. Install the right sound insulator. Refer to Instrument Panel Insulator Panel Replacement - Right Side .
  24. If the center console was removed, install the console to the vehicle. Refer to Front Floor Console Replacement .
  25. Install the left sound insulator. Refer to Instrument Panel Insulator Panel Replacement - Left Side .
  26. Connect the battery negative cable.
  27. On vehicles equipped with an automatic transmission, perform the following steps:
    27.1. Turn the ignition switch to the RUN position.
    27.2. Depress the brake pedal and shift the transmission into the PARK position.
    27.3. Release the park brake.
  28. On vehicles equipped with a manual transmission, install the shift lever.

 

GM_MASTER_DENNY, GM and ASE Master Tech/Shop Foreman
Category: Chevy
Satisfied Customers: 178
Experience: Over 15 years experience in automotive repair. GM Mark Of Excellence Winner for several years.
GM_MASTER_DENNY and 12 other Chevy Specialists are ready to help you

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