How to remove the heater core?

Here are the instructions with a diagram. If you need to enlarge the diagram save it to your picture files and then enlarge it there.

1. Disconnect battery ground cable, then drain cooling system. See: Engine, Cooling and Exhaust\Cooling System\Service and Repair

2. Disconnect heater hoses from heater core. Plug heater hoses and core fittings to prevent coolant spillage.

3. Remove bolt located below windshield wiper motor, attaching left end of plenum to dash panel.

4. Remove nut attaching upper left corner of evaporator or heater case to dash panel.
5. Disconnect vacuum control system supply hose from vacuum source, then push grommet and hose into passenger compartment.

6. Remove all instrument panel retaining screws and pull instrument panel back as far as possible without disconnecting any wire harnesses.
7. Loosen right door sill plate and remove side cowl trim panel.

8. Disengage temperature control cable housing from bracket on top of plenum. Disconnect cable from temperature blend door crank arm.

9. On models w/Automatic Temperature Control (ATC) , remove cross body brace and disconnect wiring harness from temperature blend door actuator and disconnect ATC sensor tube from evaporator case connector.
10. Disconnect vacuum harness at vacuum connector near floor air distribution duct.

11. Disconnect white vacuum hose from outside recirculating air door vacuum motor.
12. Remove two hush panels.

13. Remove one plastic push fastener retaining floor air distribution duct to left end of plenum. Remove left screw and loosen right screw on rear face of plenum. Remove floor air distribution duct.

14. Remove two screws from rear side of floor air distribution duct to plenum. To remove right screw, it may be necessary to remove the two screws attaching lower panel door vacuum motor to mounting bracket.

15. Remove push fastener attaching floor air distribution duct to left end of plenum, then remove floor air distribution duct.
16. Remove two nuts located along lower flange of plenum.
17. Carefully move plenum rearward, so that heater core tubes and plenum case upper stud clear openings in dash panel, then remove plenum from vehicle by rotating upper portion of the plenum forward, down and out from under instrument panel. It may be necessary to carefully pull lower edge of instrument panel rearward while plenum is being removed from behind instrument panel.
18. Remove retaining screws from heater core cover, then the cover from plenum assembly.

19. Remove retaining screw from heater core inlet and outlet tube bracket.

Heater core removal and installation diagram.






20. Pull heater core and seal assembly from plenum assembly.
21. Reverse procedure to install.

Section 12-03: Air Conditioning System 1992 Town Car/Crown Victoria/Grand Marquis Workshop Manual REMOVAL AND INSTALLATION Plenum Removal

1. Disconnect battery ground cable.

1. Disconnect the heater hoses from the heater core tubes. Plug the ends of the heater hoses to prevent coolant loss.

1. Plug heater core tubes securely to prevent coolant leakage from heater core during plenum removal.

1. Remove three nuts located below the windshield wiper motor retaining the LH end of the plenum to the dash panel (Fig. 15).

FIG. 15 Plenum and Air Inlet Duct Removal

1. Remove one nut retaining the upper LH corner of the evaporator case to the dash panel.

1. Remove LH and RH lower instrument panel insulators.

1. Disconnect two vacuum supply hoses from vacuum source. Push grommet and vacuum supply hose into passenger compartment.

1. Remove all instrument panel retaining screws and pull the instrument panel back as far as possible without disconnecting any wire harnesses.

1. Loosen the RH door sill plate and remove the RH side cowl trim panel.

1. On manual systems, disengage the temperature control cable housing from the bracket on top of the plenum. Disconnect the cable from the temperature blend door crank arm. On ATC systems, remove cross body brace and disconnect wiring harness from temperature blend door actuator and disconnect the ATC sensor tube from the evaporator case connector.
   

1. Disconnect the vacuum jumper harness at the multiple vacuum connector near the floor air distribution duct.

1. Disconnect the white vacuum hose from the outside-recirculating door vacuum motor.

1. Remove two hush panels.

1. Remove one plastic push fastener retaining the floor air distribution duct to the LH end of the plenum. Remove LH screw and loosen RH screw on the rear face of the plenum (Fig. 14), and remove the floor air distribution duct.

1. Remove two nuts from the two studs along the lower flange of the plenum.

1. Carefully move plenum rearward to allow heater core tubes and the stud at the top of the plenum to clear holes in the dash panel. Remove plenum from vehicle by rotating the top of the plenum forward, down and out from under the instrument panel. Carefully pull lower edge of instrument panel rearward as necessary while rolling the plenum from behind the instrument panel.

Installation

1. Route the vacuum supply hose through the dash panel and seat the grommet in the opening.

1. Position the plenum under the instrument panel with the register duct opening up and the heater core tubes down. Rotate the plenum up behind the instrument panel and position the plenum to the dash panel. Insert the heater core tubes and mounting studs through their respective holes in the dash panel and the evaporator case.

1. Install three nuts on the studs along the lower flange and one on the upper flange of the plenum (Fig. 15).

1. Install three nuts below the windshield wiper motor to attach the LH end of the plenum to the dash panel.

1. Install one nut to retain the upper LH corner of the evaporator case to the dash panel.

1. Position floor air distribution duct on plenum. Install two screws and plastic push fastener.

1. If removed, position panel door vacuum motor to the mounting bracket. Install two retaining screws.

1. Connect the white vacuum hose to the outside-recirculating door vacuum motor.

1. Connect the vacuum jumper harness to the plenum harness at the multiple vacuum connector near the floor air distribution duct. Install floor duct.

1. Connect the ATC sensor tube to the evaporator case connector on ATC equipped vehicles.

1. Install the cross body brace and connect wiring harness to the blend door actuator on ATC equipped vehicles.

1. Connect the temperature control cable housing to the bracket on top of the plenum and connect the temperature control cable to the temperature blend door crank arm. Adjust the temperature cable as outlined under Adjustments.

1. Install the bolt to attach the lower RH end of the instrument panel to the side cowl.

1. Install the RH side cowl trim panel and tighten the RH door sill plate retaining screws.

1. Install glove compartment door and check arms.

1. Connect vacuum supply hose to vacuum supply.

1. Install RH and LH lower instrument panel insulators.

1. Install two hush panels.

1. Unplug the heater core tubes and connect the heater hoses to the heater core tubes.

1. Fill the cooling system with coolant to replace coolant lost during removal of the plenum.

1. Connect the battery ground cable. Check the system for proper operation.

Disconnect both hoses from the core and one of them also from the engine. Hook the other one back to where you took one off, making a loop. The picture below is not a bronco, but gives you the idea.
By the way, your core is easy to replace. It almost pops right out from under the dash. I ahve included picture below.

Remove and replace heater core procedures:

1. Disconnect the heater hoses from the heater core tubes and plug hoses.
2. In the passenger compartment, remove the five screws attaching the heater core access cover to the plenum assembly and remove the access cover.
3. Pull the heater core rearward and down, removing it from the plenum assembly.

To install:

1. Position the heater core and seal in the plenum assembly.
2. Install the heater core access cover to the plenum assembly and secure with five screws.
3. Install the heater hoses to the heater core tubes at the dash panel in the engine compartment. Do not over-tighten hose clamps.
4. Check the coolant level and add coolant as required. Connect the negative battery cable.
5. Start the engine and check the system for coolant leaks.

in the cab, but procedures are different depending on whether or not you have A/C. See below

1980-81 Comfort Vent Heaters, Without Air Conditioning

1. Disconnect the heater hoses from the heater core tubes and plug the hoses with suitable 5 / 8 inch; (16mm) plugs.
2. Remove the glove compartment liner.
3. Remove two (2) spring clips attaching the heater core cover to the plenum along the top edge of the heater core cover.
4. Remove eight (8) screws attaching the heater core cover to the plenum and remove the cover.
5. Remove the heater core from the plenum taking care not to spill coolant from the core.

To install:

1. Install the heater core in the plenum.
2. Install the heater core cover (eight (8) screws and two (2) spring clips along the top edge of the cover).
3. Install the glove compartment liner.
4. Connect the heater hoses to the heater core. Tighten the hose clamps.
5. Add coolant to raise the coolant level to specification.
6. Check the system for proper operation and for coolant leaks.

1980-81 Standard & High Output Heaters, Without Air Conditioning

1. Disconnect the temperature cable from the temperature blend door and the mounting bracket on top of the heater case.
2. Disconnect the wires from the blower motor resistor and the blower motor.
3. Disconnect the heater hoses from the heater core and plug the hoses with suitable 5 / 8 inch; (16mm) plugs.
4. Working under the instrument panel, remove two (2) nuts retaining the left end of the heater case and the right end of the plenum to the dash panel.
5. In the engine compartment, remove one (1) screw attaching the top center of the heater case to the dash panel.
6. Remove two (2) screws attaching the right end of the heater case to the dash panel, and remove the heater case from the vehicle.
7. Remove nine (9) screws and one (1) bolt and nut attaching the heater housing plate to the heater case, and remove the heater housing plate.
8. Remove three (3) screws attaching the heater core frame to the heater case and remove the frame.
9. Remove the heater core and seal from the heater case.

To install:

1. Position the heater core and seal in the heater case.
2. Install the heater core frame (3 screws).
3. Position the heater housing plate on the heater case and install the nine (9) screws and one (1) bolt and nut.
4. Position the heater case to the dash panel and install the three (3) attaching screws.
5. Working in the passenger compartment, install two (2) nuts to retain the heater case and plenum right end to the dash panel.
6. Connect the heater hoses to the heater core. Tighten the hose clamps.
7. Connect the wires to the blower motor resistor assembly.
8. Connect the blower motor wires.
9. Position (slide) the self-adjusting clip on the temperature cable to a position approximately one 1 inch; (25.4mm) from the cable end loop.
10. Snap the temperature cable on the cable mounting bracket of the heater case. Then, position the self-adjusting clip on the door crank arm.
11. Adjust the temperature cable.
12. Check the system for proper operation.

you will have to replace the heater core if you are confirmed the heater valve is cracked.
1. Disconnect the negative battery cable.2. Drain the cooling system and disconnect the heater hoses from the heater core tubes. Plug the hoses and the heater core tubes to prevent coolant leakage.3. Remove the 3 nuts located below the windshield wiper motor attaching the left end of the plenum to the dash panel. Remove the 1 nut retaining the upper left corner of the evaporator case to the dash panel.4. Disconnect the vacuum supply hose(s) from the vacuum source. Push the grommet and vacuum supply hose(s) into the passenger compartment.5. Remove the right and left lower instrument panel insulators.6. On 1990-00 vehicles:
1. Remove the cross body brace and disconnect the wiring harness from the temperature blend door actuator.
2. Disconnect the ATC sensor tube from the evaporator case connector.
7. Disconnect the vacuum jumper harness at the multiple vacuum connector near the floor air distribution duct. Disconnect the white vacuum hose from the outside-recirculating door vacuum motor.8. Remove the 2 hush panels.9. Remove 1 plastic push fastener retaining the floor air distribution duct to the left end of the plenum. Remove the left screw and loosen the right screw on the rear face of the plenum and remove the floor air distribution duct.10. Remove the 2 nuts from the 2 studs along the lower flange of the plenum.11. Carefully move the plenum rearward to allow the heater core tubes and the stud at the top of the plenum to clear the holes in the dash panel. Remove the plenum from the vehicle by rotating the top of the plenum forward, down and out from under the instrument panel. Carefully pull the lower edge of the instrument panel rearward, as necessary, while rolling the plenum from behind the instrument panel.12. Remove the 4 retaining screws from the heater core cover and remove the cover from the plenum assembly. Pull the heater core and seal assembly from the plenum assembly.

No, you don't have to pull the whole dash board but you have to pull a few panels....here is the steps on how to get to it and remove and replace it:

1. Disconnect the negative battery cable.
   
2. Drain the cooling system and disconnect the heater hoses from the heater core tubes. Plug the hoses and the heater core tubes to prevent coolant leakage.
   

CAUTION NEVER open, service or drain the radiator or cooling system when hot; serious burns can occur from the steam and hot coolant. Also, when draining engine coolant, keep in mind that cats and dogs are attracted to ethylene glycol antifreeze and could drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantities. Always drain coolant into a sealable container. Coolant should be reused unless it is contaminated or is several years old.

1. Remove the 3 nuts located below the windshield wiper motor attaching the left end of the plenum to the dash panel. Remove the 1 nut retaining the upper left corner of the evaporator case to the dash panel.
   

Plenum removal—1990-98 vehicles

1. Disconnect the vacuum supply hose(s) from the vacuum source. Push the grommet and vacuum supply hose(s) into the passenger compartment.
   
2. Remove the right and left lower instrument panel insulators.
   

1. On 1989 vehicles:
2. Remove the 3 glove compartment hinge screws, disconnect the check arms and remove the glove compartment.
   
3. Loosen the right door sill plate and remove the right side cowl trim panel.
   
4. Remove the bolt attaching the lower right end of the instrument panel to the side cowl.
   
5. Remove the instrument panel pad as follows:
   
   • Remove the 2 screws attaching the pad to the instrument panel at each defroster opening. Be careful not to drop the screws into the defroster openings.
     
   • Remove the one screw attaching each outboard end of the pad to the instrument panel.
     
   • On Crown Victoria, remove one pad attaching screw near the upper right corner of the glove compartment door.
     
   • Remove the 5 screws attaching the lower edge of the pad to the instrument panel. Pull the instrument panel pad rearward and remove it from the vehicle.
     
6. On 1990-98 vehicles:
7. Remove all instrument panel mounting screws and pull the instrument panel back as far as it will go without disconnecting any wiring harnesses.
   
8. Make sure the nuts attaching the instrument panel braces to the dash panel are removed.
   
9. Loosen the right door sill plate and remove the right side cowl trim panel.
   
10. If equipped with manual air conditioning, disengage the temperature control cable housing from the bracket on top of the plenum. Disconnect the cable from the temperature blend door crank arm.
    
11. If equipped with Automatic Temperature Control (ATC), proceed as follows:
12. On 1989 vehicles, disconnect the temperature control cable from the ATC sensor.
    
13. Detach the vacuum harness line connector from the ATC sensor harness and detach the electrical connector from the ATC servo connector.
    
14. On 1990-98 vehicles, remove the cross body brace and disconnect the wiring harness from the temperature blend door actuator. Detach the ATC sensor tube from the evaporator case connector.
    
15. Detach the vacuum jumper harness at the multiple vacuum connector near the floor air distribution duct.
    
16. Disconnect the white vacuum hose from the outside-recirculating door vacuum motor.
    

Floor air distribution duct removal—1990-98 vehicles

1. Remove the 2 hush panels.
   
2. Remove 1 plastic push fastener retaining the floor air distribution duct to the left end of the plenum.
   
3. Remove the left screw and loosen the right screw on the rear face of the plenum and remove the floor air distribution duct.
   
4. Remove the 2 nuts from the 2 studs along the lower flange of the plenum.
   

Heater core removal—1990-98 vehicles

1. Carefully move the plenum rearward to allow the heater core tubes and the stud at the top of the plenum to clear the holes in the dash panel. Remove the plenum from the vehicle by rotating the top of the plenum forward, down and out from under the instrument panel. Carefully pull the lower edge of the instrument panel rearward, as necessary, while rolling the plenum from behind the instrument panel.
   
2. On 1989 vehicles with ATC, remove the ATC servo from the plenum.
   
3. Remove the 4 retaining screws from the heater core cover and remove the cover from the plenum assembly.
   
4. Pull the heater core and seal assembly from the plenum assembly.
   

To install:

1. Carefully install the heater core and seal assembly into the plenum assembly. Visually check to ensure that the core seal is properly positioned. Position the heater core cover and install the 4 retaining screws.
   
2. On 1989 vehicles with ATC, install the ATC servo on the plenum.
   
3. Route the vacuum supply hose through the dash panel and seat the grommet in the opening.
   
4. Position the plenum under the instrument panel with the register duct opening up and the heater core tubes down. Rotate the plenum up behind the instrument panel and position the plenum to the dash panel. Insert the heater core tubes and mounting studs through their respective holes in the dash panel and the evaporator case.
   
5. Install the 3 nuts on the studs along the lower flange and one on the upper flange of the plenum. Install the 3 nuts below the windshield wiper motor to attach the left end of the plenum to the dash panel and the one nut to retain the upper left corner of the evaporator case to the dash panel.
   
6. Position the floor air distribution duct on the plenum. Install the 2 screws and plastic push fastener. If removed, position the panel door vacuum motor to the mounting bracket and install the 2 attaching screws.
   
7. Connect the white vacuum hose to the outside-recirculating door vacuum motor. Attach the vacuum jumper harness to the plenum harness at the multiple vacuum connector near the floor air distribution duct. Install the floor duct.
   
8. If equipped with manual air conditioning, connect the temperature control cable housing to the bracket on top of the plenum and connect the temperature control cable to the temperature blend door crank arm. Adjust the temperature cable.
   
9. If equipped with ATC, proceed as follows:
   
   1. On 1989 vehicles, connect the temperature control cable to the ATC sensor and adjust the cable. Route and attach the vacuum harness connector to the ATC sensor and attach the electrical connector to the ATC servo connector. Do not block the sensor aspirator exhaust port with the excess vacuum harness. Install the ATC sensor tube between the sensor and the evaporator connector.
      
   2. On 1990-98 vehicles, attach the ATC sensor tube to the evaporator case connector. Install the cross body brace and connect the wiring harness to the blend door actuator.
      
10. Install the bolt to attach the lower right end of the instrument panel to the side cowl. Install the right side cowl trim panel and tighten the right door sill plate attaching screws.
    
11. On 1989 vehicles, install the instrument panel pad and the glove compartment door. On 1990-98 vehicles, push the instrument panel back into position and install all instrument panel mounting screws. Install the right and left lower instrument panel insulators.
    
12. Connect the vacuum supply hose(s) to the vacuum source.
    
13. Install the right and left lower instrument panel insulators and install the 2 hush panels.
    
14. Unplug the heater core tubes and the heater hoses and connect the heater hoses to the heater core tubes. Fill the cooling system.
    
15. Connect the negative battery cable and check the system for proper operation.
    

big job, dificulty 8 on a 10 scale Heater Air Plenum Chamber Removal

1. Remove heater outlet floor duct (18C433) as described.
   

1. Remove instrument panel (04320). Refer to Section 01-12 .
   

Instrument Panel SPECIAL SERVICE TOOL(S) REQUIRED Description Tool Number Radio Removing Tool 415-001 (T87P-19061-A)
Removal and Installation

1. Disconnect battery ground cable (14301).
   

1. Remove RF wheel and tire assembly. Refer to Section 04-04 .
   

1. Remove three nuts in radiator coolant recovery reservoir area.
   

1. Remove bolt retaining front fender apron (16054) to front fender (16005) .
   

1. Position front fender splash shield out of the way.
   

1. Lower vehicle.
   

1. Tag and remove main harness connector from jumper harness (located in front of blower motor).
   

1. Remove steering column. Refer to Section 11-04 .
   

1. Remove RH cowl side trim panel (02344) and LH cowl side trim panels (02345) .
   

1. Tag and disconnect wiring connectors in LH and RH cowls.
   

1. Remove ground wire located on LH cowl side.
   

1. Remove RH instrument panel upper moulding (04268) and LHinstrument panel moulding (04389) from instrument panel (04320) by pulling away from instrument panel and snapping out of retainers. Disconnect wiring connectors as required.
   

1. Remove glove compartment (06010).
   

1. Remove instrument panel upper finish panel (044A90) and disconnect the A/C sunload sensor (19E663) and anti-theft indicator, if equipped.
   

1. Disconnect the heater water hoses (18472) from the heater core tubes. Plug the ends of the heater water hoses to prevent coolant loss.
   

1. Plug heater core tubes securely to prevent coolant leakage from heater core (18476).
   

1. Remove one nut retaining the upper LH corner of the A/C evaporator core housing (19A559) to the dash panel (01610) .
   

1. Disconnect two vacuum supply hoses from vacuum source. Push grommet and vacuum supply hose into passenger compartment.
   

1. Disconnect wiring harness from A/C electronic blend door actuator.
   

1. Disconnect the white vacuum hose from the heater and A/C air inlet duct door vacuum control motor (18A318).
   

1. Remove nuts from the studs along the lower flange of the heater air plenum chamber (18471).
   

1. Disconnect connectors to A/C electronic blend door actuator and electronic module on side of heater air plenum chamber.
   

1. Remove heater air plenum chamber by pulling rearward.
   

Heater Air Plenum Chamber and Air Inlet Duct





Item Part Number Description 1 19C836 Suction Accumulator/Drier 2 56956-S2 Screw (2 Req'd) 3 386877-S36 Screw 4 45445-S36 Nut and Washer Assy 5 19C928 A/C Recirculating Air Duct Screen 6 386877-S36M Screw (2 Req'd) 7 45332-S12 Nut and Washer 8 19B762 A/C Air Inlet Door Inner Seal 9 19C590 A/C Recirculating Air Duct 10 18471 Heater Air Plenum Chamber 11 18C433 Heater Outlet Floor Duct 12 55734-S2 Nut 13 19A559 A/C Evaporator Core Housing 14 45332-S2 Nut and Washer A — Tighten to 2.5-3.2 Nm (23-28 Lb-In)
Installation

1. Route the vacuum supply hose through the dash panel and seat the grommet in the opening.
   

1. Position the heater air plenum chamber under the instrument panel with the A/C register duct opening up and the heater core tubes down. Connect wire harness connector to A/C electronic blend door actuator and electronic module on side of heater air plenum chamber .
   

1. Rotate the heater air plenum chamber up behind the instrument panel and position the heater air plenum chamber to the dash panel. Insert the heater core tubes and mounting studs through their respective holes in the dash panel and the A/C evaporator core housing.
   

1. Install three nuts on the studs along the lower flange and one on the upper flange of the heater air plenum chamber.
   

1. Install three nuts below the windshield wiper motor (17508) to retain the LH end of the heater air plenum chamber to the dash panel.
   

1. Install one nut to retain the upper LH corner of the A/C evaporator core housing to the dash panel .
   

1. Connect the white vacuum hose to the heater and A/C air inlet duct door vacuum control motor.
   

1. Connect the vacuum jumper harness to the plenum harness at the multiple vacuum connector near the heater outlet floor duct. Install heater outlet floor duct.
   

1. Connect the sensor tube to the evaporator case connector on EATC-equipped vehicles.
   

1. Connect vacuum supply hose to vacuum supply.
   

1. Unplug the heater core tubes and connect the heater water hoses to the heater core tubes.
   

1. Fill the cooling system with coolant to replace coolant lost during removal of the heater air plenum chamber.
   

1. Install heater outlet floor duct as described.
   

1. Install instrument panel. Refer to Section 01-12 .
   

Section 12-03A: Air Conditioning System—Manual A/C-Heater 1998 Crown Victoria, Grand Marquis Workshop Manual
REMOVAL AND INSTALLATION Heater Core Removal
NOTE: If a heater core leak is suspected, the heater core must be pressure leak tested before it is removed from the vehicle. Refer to Section 12-00 .

1. Remove the heater air plenum chamber (18471) assembly as described.
   

1. Remove the heater dash gasket (18570) from the heater air plenum assembly.
   

1. Remove the four retaining screws from the heater core cover (18B300) and remove the heater core cover from the heater air plenum chamber assembly.
   

you will have to remove the dash board and the heater box its a really big job but if you have the dedication and the time it can be done ...good luck

wow. just did this one today. all i can say is have patience. you just have to take the dash completly apart top to bottom. you have to lower your steering colume to. you dont have to take the dash out of the car when you get it off enough on the passanger side just tie it up to the handle at the roof and you got access to the black box on the passanger side. you have to go under the hood and remove two bolts and two hoses to release the black box so you can get the heater core out. you also dont want to forget to disconnect the battery and drain your radiator. I watched my husban do this and i dont know how else to explain this or give better detail i hope i helped.

you have to remove the plenum case behind the dash. I will provide 94 gr marquis. don't have 84.



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Section 12-03A: Air Conditioning System—Manual A/C-Heater 1994 Crown Victoria/Grand Marquis. Workshop Manual
REMOVAL AND INSTALLATION Heater Core Removal

1. Remove the heater air plenum chamber assembly as outlined.
2. Heater Air Plenum Chamber Removal
   
   1. Disconnect battery ground cable .
   1. Disconnect the heater water hoses from the heater core tubes. Plug the ends of the heater water hoses to prevent coolant loss.
   1. Plug heater core tubes securely to prevent coolant leakage from heater core during heater air plenum chamber removal.
   1. Remove three nuts located below the windshield wiper motor (17508) retaining the LH end of the heater air plenum chamber to the dash panel .
   1. Remove one nut retaining the upper LH corner of the A/C evaporator core housing to the dash panel .
   1. Remove LH and RH lower instrument panel insulators.
   1. Disconnect two vacuum supply hoses from vacuum source. Push grommet and vacuum supply hose into passenger compartment.
   1. Remove all instrument panel retaining screws and pull the instrument panel back as far as possible without disconnecting any wire harnesses.
   1. Loosen the RH door sill plate and remove the RH side cowl trim panel.
   1. Remove cross body brace and disconnect wiring harness from A/C electronic door actuator motor (19E616) and disconnect the sensor tube from the evaporator case connector.
   1. Disconnect the vacuum jumper harness at the multiple vacuum connector near the heater outlet floor duct.
   1. Disconnect the white vacuum hose from the heater and A/C air inlet duct door vacuum control motor.
   1. Remove two hush panels.
   1. Remove one plastic push fastener retaining the heater outlet floor duct to the LH end of the heater air plenum chamber . Remove LH screw and loosen RH screw on the rear face of the heater air plenum chamber and remove the heater outlet floor duct .
   1. Remove two nuts from the two studs along the lower flange of the heater air plenum chamber .
   1. Carefully move heater air plenum chamber rearward to allow heater core tubes and the stud at the top of the heater air plenum chamber to clear holes in the dash panel. Remove heater air plenum chamber from vehicle by rotating the top of the heater air plenum chamber forward, down and out from under the instrument panel . Carefully pull lower edge of instrument panel rearward as necessary while rolling the heater air plenum chamber from behind the instrument panel .

1. Remove the four retaining screws from the heater core cover (18B300) and remove the heater core cover from the heater air plenum chamber assembly.
   
   Heater Core Removal
   
   
   
   
   
   Item Part Number Description 1 390092-S2 Screw (2 Req'd) 2 18658 Heater Core Case Seal 3 18476 Heater Core 4 18570 Heater Dash Gasket 5 18471 Heater Air Plenum Chamber 6 18B300 Heater Core Cover

1. Pull the heater core assembly from the heater air plenum chamber assembly.

Installation

1. Carefully install heater air plenum chamber assembly into the heater air plenum chamber assembly. Visually check to ensure that core seal is properly positioned.

1. Position the heater core cover and install the four retaining screws.

1. Install the heater air plenum chamber assembly as outlined.