Mazda Trucks 1972-1986 Repair Guide

Heater Assembly

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REMOVAL & INSTALLATION



  1. Disconnect the battery ground cable.
  2.  
  3. Drain the cooling system.
  4.  


CAUTION
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 quantity. Always drain coolant into a sealable container. Coolant should be reused unless it is contaminated or is several years old.

  1. Remove the water valve shield at the left side of the heater.
  2.  
  3. Disconnect the two hoses from the left side of the heater.
  4.  
  5. At the heat-defroster door, the water valve and the outside recirculation door, disengage the control cable housing from the mounting clip on the heater. Disconnect each of the three cable wires from the crank arms.
  6.  
  7. Disconnect the fan motor electrical lead.
  8.  
  9. Remove the glove compartment for clearance.
  10.  
  11. Working inside the engine compartment, remove the two retaining nuts and the single bolt and washer which hold the heater to the firewall. Later models also have a retaining bolt inside the passenger compartment which must be removed.
  12.  
  13. Disconnect the two defroster ducts from the heater and remove the heater.
  14.  

To install:
  1. Install the heater on the dash so that the heater duct indexes with the air intake duct and the two mounting studs enter their respective holes.
  2.  
  3. From the engine side of the firewall, install the nuts on the mounting studs. While an assistant holds the heater in position, install the mounting bolt.
  4.  
  5. Connect the defroster ducts.
  6.  
  7. Connect the heat-defrost door control cable to the door crank arm. Set the control lever (upper) in the HEAT position and turn the crank arm toward the mounting clip as far as it will go. Engage the cable housing in the clip and install the screw in the clip.
  8.  
  9. Connect the water valve control cable wire to the crank arm on the water valve lever. Locate the cable housing in the mounting clip. Set the control lever in the HOT position and pull the valve plunger and lever to the full outward position. This will move the lever crank arm toward the cable mounting clip as far as it will go. Tighten the clip and screw.
  10.  
  11. Insert the outside recirculation door control cable into the hole in the door crank arm. Bend the wire over and tighten the screw Set the center control lever in the REC position and turn the door crank arm toward the mounting clip as far as it will go. Engage the cable housing in the clip and install the screw in the clip.
  12.  
  13. Connect the fan motor electrical lead.
  14.  
  15. Connect the two hoses to the heater core tubes, at the left side of the heater, and tighten the clamp.
  16.  
  17. Install the water valve shield and tighten the three screws (left side of the heater).
  18.  
  19. Refill the cooling system and connect the battery ground cable.
  20.  
  21. Run the engine and check for leaks. Check the operation of the heater.
  22.  
  23. Replace the glove compartment.
  24.  

 
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