Chrysler Full-Size Trucks 1989-1996 Repair Guide

Heater Core

Print

REMOVAL & INSTALLATION



Dakota
WITHOUT AIR CONDITIONING
  1. Disconnect the negative battery cable. Drain the coolant.
  2.  
  3. Remove the steering column cover, intermittent wiper control, if equipped and the lower instrument panel module retaining screw to the right of the steering column.
  4.  
  5. Remove the center distribution duct retaining screws and panel support screw at the bottom of the module.
  6.  
  7. Remove the courtesy lamp at the lower right corner of the module and the screw near the ash receiver.
  8.  
  9. Open the glovebox and remove the screws along the top edge.
  10.  
  11. Move the module out and down far enough to unclip the wiring harness and antenna cable and disconnect the speaker wire (if equipped with monaural radio) and glovebox light wire. Remove the module from the vehicle.
  12.  
  13. Remove the center air distribution duct.
  14.  
  15. Remove the antenna wire from retaining clip at the right end of the heater unit.
  16.  
  17. Disconnect the blower motor connector and remove the thermal insulator retainer from the heater unit.
  18.  
  19. Disconnect the demister hoses from the adaptor at the top of the heater unit.
  20.  
  21. Disconnect the vacuum feed line from the check valve.
  22.  
  23. Disconnect the temperature control cable flag retainer from the heater unit.
  24.  
  25. Remove the adjusting clip from the blend air door crank.
  26.  
  27. Disconnect the heater hoses from the core tubes and plug them.
  28.  
  29. Remove the four heater unit attaching nuts from the rear engine compartment dash panel.
  30.  
  31. Remove the heater unit support attaching screw and rotate the brace out of the way.
  32.  
  33. Remove the heater unit from the vehicle.
  34.  
  35. To disassemble the housing assembly, vacuum diaphragm and retaining screws from the cover and remove the cover.
  36.  
  37. Remove the retaining screw from the heater core and remove the core from the housing assembly.
  38.  

To install:
  1. Remove the temperature control door from the unit and clean the unit out with solvent. Lubricate the lower pivot rod and its well and install. Wrap the heater core with foam tape and place it in position. Secure it with its screw.
  2.  
  3. Assemble the unit, making sure all vacuum tubing is properly routed.
  4.  
  5. Install the assembly to the vehicle and connect the vacuum harness. Install the nuts to the firewall. Install the support brace to the heater unit.
  6.  
  7. Connect the demister hoses to the adaptor at the top of the heater unit.
  8.  
  9. Connect the blower motor connector and install the thermal insulator retainer to the heater unit.
  10.  
  11. Connect the vacuum feed line to the check valve.
  12.  
  13. Connect the temperature control cable flag retainer to the heater unit and install the adjusting clip from the blend air door crank.
  14.  
  15. Install the center air distribution duct.
  16.  
  17. Install the antenna wire from retaining clip at the right end of the heater unit.
  18.  
  19. Install the instrument panel module and all related parts.
  20.  
  21. Connect the heater hoses to the core tubes.
  22.  
  23. Fill the cooling system.
  24.  
  25. Connect the negative battery cable and check the heater for proper operation and leakage.
  26.  

WITH AIR CONDITIONING
  1. Disconnect the negative battery cable. Properly discharge the air conditioning system. Drain the coolant.
  2.  
  3. Remove the steering column cover, intermittent wiper control and the lower instrument panel module retaining screw to the right of the steering column.
  4.  
  5. Remove the center distribution duct retaining screws and panel support screw at the bottom of the module.
  6.  
  7. Remove the courtesy lamp at the lower right corner of the module and the screw near the ash receiver.
  8.  
  9. Open the glovebox and remove the screws along the top edge.
  10.  
  11. Move the module out and down far enough to unclip the wiring harness and antenna cable and disconnect the speaker wire (if equipped with monaural radio) and glovebox light wire. Remove the module from the vehicle.
  12.  
  13. Remove the center air distribution duct.
  14.  
  15. Remove the antenna wire from retaining clip at the right end of the heater unit.
  16.  
  17. Disconnect the blower motor connector and remove the thermal insulator retainer from the heater unit.
  18.  
  19. Disconnect the demister hoses from the adaptor at the top of the heater unit.
  20.  
  21. Disconnect the vacuum harness connector from the air conditioning control hose and vacuum feed line from the check valve.
  22.  
  23. Disconnect the temperature control cable flag retainer from the heater unit and remove the adjusting clip from the blend air door crank.
  24.  
  25. Disconnect the heater hoses from the core tubes and plug them.
  26.  
  27. Remove the condensation drain tube.
  28.  
  29. Remove the 4 heater/air conditioning unit attaching nuts from the rear engine compartment dash panel.
  30.  
  31. Remove the heater/air conditioning unit support attaching screw and rotate the brace out of the way.
  32.  
  33. Remove the heater/air conditioning unit from the vehicle.
  34.  
  35. To disassemble the housing assembly, vacuum diaphragm and retaining screws from the cover and remove the cover.
  36.  
  37. Remove the retaining screw from the heater core and remove the core from the housing assembly.
  38.  

To install:
  1. Remove the temperature control door from the unit and clean the unit out with solvent. Lubricate the lower pivot rod and its well and install. Wrap the heater core with foam tape and place it in position. Secure it with its screw.
  2.  
  3. Assemble the unit, making sure all vacuum tubing is properly routed.
  4.  
  5. Install the assembly to the vehicle and connect the vacuum harness. Install the nuts to the firewall and install the condensation tube. Install the support brace to the heater/air conditioning unit.
  6.  
  7. Connect the demister hoses to the adaptor at the top of the heater unit.
  8.  
  9. Connect the blower motor connector and install the thermal insulator retainer to the heater unit.
  10.  
  11. Connect the vacuum harness connector to the air conditioning control hose and vacuum feed line to the check valve.
  12.  
  13. Connect the temperature control cable flag retainer to the heater unit and install the adjusting clip from the blend air door crank.
  14.  
  15. Install the center air distribution duct.
  16.  
  17. Install the antenna wire from retaining clip at the right end of the heater unit.
  18.  
  19. Install the instrument panel module and all related parts.
  20.  
  21. Connect the heater hoses to the core tubes.
  22.  
  23. Using new gaskets, install the H-valve and connect the hose connection at the valve.
  24.  
  25. Evacuate and recharge the air conditioning system.
  26.  
  27. Fill the cooling system.
  28.  
  29. Connect the negative battery cable and check the entire climate control system for proper operation and leakage.
  30.  

1989-93 Pick-Up and Ramcharger

See Figure 1

WITHOUT AIR CONDITIONING
  1. Disconnect the negative battery cable.
  2.  
  3. Drain the cooling system. Remove and plug the heater core hoses.
  4.  
  5. Remove the right side cowl trim panel, if equipped. Remove the glove box assembly. Remove the structural brace through the glovebox opening.
  6.  
  7. Remove the right half of the instrument panel lower reinforcement and disconnect the ground strap.
  8.  



Click image to see an enlarged view

Fig. Fig. 1: Disconnect the heater (water) hoses when removing the heater core

  1. Disconnect the control cables from the heater housing and the blower motor wires on the engine side.
  2.  
  3. Remove the retaining screw between the package to cowl side sheet metal.
  4.  
  5. Remove the heater housing retaining nuts on the engine side of the heater assembly and remove the heater housing assembly.
  6.  
  7. Remove the heater housing cover retaining screws and the mode door crank. Separate the cover from the housing.
  8.  
  9. Carefully lift the heater core from the heater housing.
  10.  

To install:
  1. Clean the inside of the housing. Install the heater core into the housing.
  2.  
  3. Install the housing cover.
  4.  
  5. Inspect the dash panel seal for damage and repair as required.
  6.  
  7. Install the assembly to the dash panel and install the retaining nuts.
  8.  
  9. Install the cowl side retaining screws.
  10.  
  11. Connect the blower motor connector.
  12.  
  13. Connect the control cables.
  14.  
  15. Install the right lower instrument panel reinforcement, structural brace, glove box and cowl side trim panel, if equipped.
  16.  
  17. Connect the heater hoses.
  18.  
  19. Refill the radiator.
  20.  
  21. Connect the negative battery cable, run the vehicle until the thermostat opens, fill the radiator completely and check the operation of the heater.
  22.  
  23. Once the vehicle has cooled, recheck the coolant level.
  24.  

WITH AIR CONDITIONING
  1. Disconnect the negative battery cable. Properly discharge the air condition system. Drain the cooling system. Disconnect and plug the heater hoses and the refrigerant lines.
  2.  
  3. Remove the condensation tube from the housing.
  4.  
  5. Move the transfer case and gear shift levers away from the instrument panel, if equipped.
  6.  
  7. Remove the right side cowl trim panel, if equipped. Remove the glove box and swing it out from the bottom.
  8.  
  9. Remove the structural brace from the through hole in the glove box opening. Remove the ash receiver.
  10.  
  11. Remove the right lower half of the dash reinforcement by removing the retaining screws holding it to the instrument panel and to the cowl side trim panel.
  12.  
  13. Disconnect the radio ground strap, if equipped. Remove the center and floor air distribution ducts.
  14.  
  15. Disconnect the temperature control cable from the assembly and tape it out of the way.
  16.  
  17. Disconnect the vacuum lines from the extension on the control unit and unclip the vacuum lines from the defroster duct.
  18.  
  19. Remove the wiring connector from the resistor block. Remove the blower motor electrical connector from the engine side of the assembly.
  20.  
  21. Disconnect the vacuum lines on the engine side and make sure the grommet is free from the dash panel.
  22.  
  23. Remove the retaining nuts on the engine side. Remove the screw that retains the assembly to the cowl side of the sheet metal.
  24.  
  25. Remove the assembly from the vehicle.
  26.  
  27. Remove the vacuum actuators, door crank levers, evaporator case cover retaining nuts and screws and the heater core retaining screws. Lift the cover off of the assembly and remove the heater core from its mounting.
  28.  

To install:
  1. Clean the inside of the housing. Install the heater core into the housing.
  2.  
  3. Install the housing cover, retaining screws and nuts, levers and actuators.
  4.  
  5. Inspect the dash panel seals for damage and repair as required.
  6.  
  7. Feed the vacuum lines through the hole in the dash panel, install the assembly to the dash panel and install all retaining nuts and screws.
  8.  
  9. Connect the resistor block and blower motor.
  10.  
  11. Connect the vacuum lines to the extension on the control unit and clip the vacuum lines to the defroster duct.
  12.  
  13. Connect the temperature control cable to the assembly.
  14.  
  15. Connect the radio ground strap, if equipped. Install the center and floor air distribution ducts.
  16.  
  17. Install the dash reinforcement, structural brace, glove box and right side cowl trim panel, if equipped. Install the ash receiver.
  18.  
  19. Install the condensation tube.
  20.  
  21. Connect the heater hoses and vacuum lines.
  22.  
  23. Install a new gasket and connect the refrigerant lines.
  24.  
  25. Evacuate and recharge the air conditioning system. Refill the radiator.
  26.  
  27. Connect the negative battery cable, run the vehicle until the thermostat opens, fill the radiator completely and check the operation of the entire climate control system.
  28.  
  29. Once the vehicle has cooled, recheck the coolant level.
  30.  

1994-96 Pick-Ups

  1. Remove the heater/air conditioning housing (as described in this section).
  2.  
  3. Remove the heater core retaining screws.
  4.  
  5. Pull the heater core straight out of the housing.
  6.  

To install:
  1. Install the heater core into the housing.
  2.  
  3. Position the clips over the heater core tubes. Install and tighten the screws.
  4.  
  5. Install the heater/air conditioning housing.
  6.  

 
AutoZone Logo