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eric, Automotive Repair Shop Manager
Category: Nissan
Satisfied Customers: 32382
Experience:  Automotive Repair Shop Manager, Technician/JA Mentor
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1993 Nissan pickup: detailed instructions..a heater core..d21

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Where do I find a complete & detailed instructions on how to replace a heater core on a 1993 Nissan pickup d21

Nissan doesnt really give great directions, but from experience, you will need to first remove the dash assembly:

  1. Disconnect the negative battery cable.
  2. Remove the radio.

Click image to see an enlarged view

Fig. Fig. 1: Exploded view of the instrument panel assembly and console-all models similar

  1. Remove the ashtray.
  2. Remove the control head.
  3. Remove the mounting screws and pull out the center console. Disconnect the cigarette lighter and remove the console.
  4. Press in the connecting pawls, then remove the left and right side window defroster outlets.
  5. Press in the connecting pawls and remove the two fresh air ducts.
  6. Carefully press in the connecting clips and remove the three defroster ducts.
  7. Remove the assembly retaining screws and lift out the panel and pad assembly.

I know the above diagram doesnt blow up big, so here it is in sections to blow up to see all screws and clips:



heater assembly:
  1. Disconnect the negative battery cable.
  2. Drain the cooling system.

When draining the coolant, keep in mind that cats and dogs are attracted by 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 duct(s) and disconnect the heater hoses at the heater housing assembly.
  2. Remove the console box and instrument panel assembly (if necessary).

Click image to see an enlarged view

Fig. Fig. 1: Exploded view of the heater assembly-all models similar


  1. graphic
  2. Disconnect the air intake control cable from the housing assembly. Remove all necessary electrical connections.
  3. On models equipped with A/C, remove the evaporator unit (do not discharge the A/C system) nuts and bolts, but do not remove the evaporator unit from the vehicle.
  4. Remove the heater housing assembly.

To install:
  1. Install the heater assembly and tighten the mounting screws.
  2. Install the evaporator unit assembly on A/C models.
  3. Connect the air intake control cable. Reconnect all necessary electrical connections.
  4. Install the instrument panel assembly and console box.
  5. Install the heater duct(s).
  6. Connect the heater hoses.
  7. Connect the negative battery cable and fill the engine with coolant. Adjust the control cable for proper operation. Start the engine and check for any coolant leaks. Check the A/C and heating systems for proper operation.

  1. Remove the screws and clips and separate the heater case halves.
  2. Slide out the heater core.

To install:
  1. Install the heater core in the heater case and close the two halves. Install the clips.
  2. Install the heater assembly.

Click image to see an enlarged view

Fig. Fig. 1: Exploded view of the heater core mounting-all models

Edited by eric on 11/29/2010 at 11:19 PM EST
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