Honda Accord/Civic/Prelude 1973-1983 Repair Guide

Heater Assembly

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REMOVAL & INSTALLATION



See Figures 1 through 10

Civic (1973-79)

This procedure does not apply to vehicles equipped with air conditioning. On vehicles equipped with air conditioning, removal may differ from the procedures listed below. Only a trained air conditioning specialist should disassemble air conditioning equipped units. Air conditioning units contain pressurized freon which can be extremely dangerous (e.g. frostbite burns and/or blindness) to the untrained.

  1. Drain the radiator.
  2.  


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by the ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

  1. Disconnect the right and left defroster hoses.
  2.  
  3. Disconnect the inlet and outlet water hoses at the heater assembly.
  4.  

There will be a coolant leakage when disconnecting the hoses. Catch the coolant in a container to prevent damage to the interior.

  1. Disconnect the following items:
    1. Fre/Rec control cable.
    2.  
    3. Temperature control rod.
    4.  
    5. Room/Def. control cable.
    6.  
    7. Fan motor switch connector.
    8.  
    9. Upper attaching bolts.
    10.  
    11. Lower attaching bolts.
    12.  
    13. Lower bracket.
    14.  

  2.  
  3. Remove the heater assembly through the passenger side.
  4.  

To install:
  1. Install the heater assembly by reversing the removal procedure. Pay attention to the following points:
    1. When installing the heater assembly, do not forget to connect the motor ground wire to the right side of the upper bracket.
    2.  
    3. Connect the inlet and outlet water hoses SECURELY.
    4.  

  2.  

The inlet hose is a straight type, and the outlet hose is an L-type.

    1. Install the defroster nozzles in the correct position.
    2.  
    3. Connect the control cables securely. Operate the control valve and lever to check for proper operation.
    4.  
    5. Be sure to bleed the cooling system (see General Information & Maintenance ).
    6.  




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Fig. Fig. 1: Typical view of blower motor assembly



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Fig. Fig. 2: View of heater hoses-note heater hose clamp positioning



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Fig. Fig. 3: Removing the heater hoses



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Fig. Fig. 4: Removing the lower trim panel retaining screws



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Fig. Fig. 5: Removing the lower trim panel



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Fig. Fig. 6: Removing the cover panel retaining clips



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Fig. Fig. 7: Removing the cover panel



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Fig. Fig. 8: View of the heater ducts



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Fig. Fig. 9: Mark and disconnect all vacuum hoses for the heater assembly



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Fig. Fig. 10: Removing the blower motor assembly for the heater assembly

Civic (1980-83)

This procedure does not apply to vehicles equipped with air conditioning. On vehicles equipped with air conditioning, removal may differ from the procedures listed below. Only a trained air conditioning specialist should disassemble air conditioning equipped units. Air conditioning units contain pressurized freon which can be extremely dangerous (e.g. frostbite burns and/or blindness) to the untrained.

  1. Drain the radiator.
  2.  


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by the ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

  1. Remove the dashboard.
  2.  
  3. Disconnect both heater hoses at the firewall and drain the coolant into a container.
  4.  
  5. Remove the heater lower mounting nut on the firewall.
  6.  
  7. Remove the two heater duct retaining clips.
  8.  
  9. Disconnect the control cables from the heater.
  10.  
  11. Remove the heater valve cable cover. Remove the heater assembly.
  12.  

To install:
  1. Reverse the removal procedures. Bleed cooling system and make sure cables are properly adjusted. Apply a sealant to the grommets and make sure inlet and outlet hoses are connected to the right connections and are secure.
  2.  

Accord (1976-83)

See Figure 11

This procedure does not apply to vehicles equipped with air conditioning. On vehicles equipped with air conditioning, removal may differ from the procedures listed below. Only a trained air conditioning specialist should disassemble air conditioning equipped units. Air conditioning units contain pressurized freon which can be extremely dangerous (e.g. frostbite burns and/or blindness) to the untrained.

  1. The heater blower assembly can be removed by disconnecting the battery cable, removing the glove box, the fresh air control cable, and the three bolts that hold the blower.
  2.  
  3. Drain the radiator. Remove the heater hose connections.
  4.  


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by the ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

  1. Remove the instrument panel.
  2.  
  3. Once the instrument panel is removed, remove the heater assembly mounting bolts.
  4.  



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Fig. Fig. 11: Typical heater assembly

  1. Remove the control cables from their clips. Remove all necessary hoses. Remove the heater assembly.
  2.  
  3. Remove the left and right upper bolts for heater assembly.
  4.  
  5. Remove the lower bolts from the heater assembly and remove the heater core.
  6.  

To install:
  1. Reverse the removal procedures. Keep the following points in mind:
    1. Don't interchange the inlet and outlet water hoses.
    2.  
    3. Make sure all the cables operate correctly.
    4.  
    5. Bleed the air from the cooling system (see General Information & Maintenance ).
    6.  

  2.  

Prelude 1979-82

This procedure does not apply to vehicles equipped with air conditioning. On vehicles equipped with air conditioning, removal may differ from the procedures listed below. Only a trained air conditioning specialist should disassemble air conditioning equipped units. Air conditioning units contain pressurized freon which can be extremely dangerous (e.g. frostbite burns and/or blindness) to the untrained.

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the glove box.
  4.  
  5. Remove the blower-to-heater case bolts and the blower.
  6.  
  7. Drain the coolant.
  8.  


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by the ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

  1. Remove the lower dash panel.
  2.  
  3. Place a drain pan under the case and disconnect both heater hoses from the core tubes.
  4.  
  5. Remove the lower heater-to-firewall nut.
  6.  
  7. Disconnect the cable at the water valve.
  8.  
  9. Remove the control cables from the heater case.
  10.  
  11. Remove the upper heater mount bolts and the heater assembly.
  12.  

To install:
  1. Reverse the removal procedures. Keep the following points in mind:
    1. Don't interchange the inlet and outlet water hoses.
    2.  
    3. Make sure all the cables operate correctly.
    4.  
    5. Bleed the air from the cooling system (see General Information & Maintenance ).
    6.  

  2.  

Only the Prelude (1983) model may have the heater core replaced without removing the heater assembly. On all other models remove the heater assembly then remove the heater core from the heater assembly.

Prelude (1983)
  1. Drain the cooling system. Remove the heater pipe cover and heater pipe clamps.
  2.  


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by the ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

  1. Remove the heater core retaining plate.
  2.  
  3. Pull the cotter pin out of the hose clamp joint and separate the heater pipes.
  4.  

Engine coolant will drain from the heater pipes when they are disconnected. Place a drip pan under the pipes to catch the coolant.

  1. When all the coolant has drained from the heater core, remove it from the heater housing.
  2.  

To install:
  1. Reverse the removal procedures noting the following points:
    1. Replace the hose clamps with new ones.
    2.  
    3. Turn the cotter pin in the hose clamps tightly to prevent leaking coolant.
    4.  
    5. Refill the cooling system with coolant and open the bleed bolt until coolant begins to flow from it. Tighten the bolt when all the air has escaped from the system.
    6.  

  2.  

 
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