Chevrolet Blazer/Jimmy 1969-1982 Repair Guide

Heater Core

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REMOVAL & INSTALLATION



1969-72 Models
WITHOUT AIR CONDITIONING


Click image to see an enlarged view

Fig. Fig. 1 Sectional views of the heater controls-1969-72 models


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. Drain the cooling system and disconnect the battery.
  2.  
  3. Remove the electrical connection at the blower.
  4.  
  5. Remove the heater hoses at the core tubes.
  6.  
  7. Loosen and move the right front fender skirt. Remove enough screws so that the skirt can be moved outward.
  8.  
  9. Working from under the dash, remove the seal on the temperature door cable and disconnect the cable from the temperature door.
  10.  
  11. Pull the case away from the mounting studs after removing the retaining bolts and nuts.
  12.  
  13. Remove the core retainers and remove the core.
  14.  
  15. Installation is the reverse of removal.
  16.  

1969-72 Models
WITH FACTORY INSTALLED AIR CONDITIONING

Models with dealer installed air conditioning use the same procedure as those without air conditioning.


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. Drain the coolant. Disconnect the battery ground cable.
  2.  
  3. Detach the heater hoses from the core tubes at the firewall.
  4.  
  5. Remove the stud nuts on the engine side of the firewall.
  6.  
  7. Remove the glove box.
  8.  
  9. Unplug the relay connector and remove the right ball outlet hose.
  10.  
  11. Remove the screw holding the panel outlet air distributor to the heater case. Remove the heater case retaining screws.
  12.  
  13. Pull the heater case away from the firewall; reach in and disconnect the resistor connector. Remove the resistor harness grommet and remove the harness.
  14.  
  15. Remove the heater case. Remove the core mounting straps.
  16.  
  17. Installation is the reverse of removal.
  18.  

1973-82 Models
WITHOUT AIR CONDITIONING


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Fig. Fig. 2 Heater di