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For 1990-2009 cars only

Auxiliary Air Conditioning Evaporator Replacement Tahoe/Yukon

Tools Required

J 39400-A Halogen Leak Detector

Removal Procedure


    Object Number: 612394  Size: SH
  1. Remove the auxiliary HVAC module (4) from the vehicle. Refer to Auxiliary HVAC Module Replacement .

  2. Object Number: 621729  Size: SH
  3. Remove the air temperature actuator (1) from the auxiliary HVAC module.

  4. Object Number: 621730  Size: SH
  5. Remove the heater core cover (1) from the auxiliary HVAC module.

  6. Object Number: 621732  Size: SH
  7. Remove the heater core (1) from the auxiliary HVAC module.

  8. Object Number: 625745  Size: SH
  9. Remove the lower module cover from the auxiliary HVAC module.

  10. Object Number: 625733  Size: SH
  11. Remove the evaporator core from the lower module cover.

Installation Procedure


    Object Number: 625733  Size: SH
  1. Install the evaporator core to the lower module cover.

  2. Object Number: 625745  Size: SH
  3. Install the lower module cover to the auxiliary HVAC module.

  4. Object Number: 621732  Size: SH
  5. Install the heater core (1) to the auxiliary HVAC module.

  6. Object Number: 621730  Size: SH
  7. Install the heater core cover (1) to the auxiliary HVAC module.

  8. Object Number: 621729  Size: SH
  9. Install the air temperature actuator (1) to the auxiliary HVAC module.

  10. Object Number: 612394  Size: SH
  11. Install the auxiliary HVAC module assembly  (4) to the vehicle. Refer to Auxiliary HVAC Module Replacement .

Auxiliary Air Conditioning Evaporator Replacement Suburban/Yukon XL

Tools Required

J 39400-A Halogen Leak Detector

Removal Procedure


    Object Number: 612400  Size: SH
  1. Remove the auxiliary HVAC module (3) from the vehicle. Refer to Auxiliary HVAC Module Replacement .

  2. Object Number: 615126  Size: SH
  3. Remove the air temperature actuator (1).
  4. Remove the stud on the underside of the rear HVAC module between the heater core inlet and outlet pipes (4).
  5. Carefully separate the heater core pipe gasket from the module case and remove the heater core pipe retainer.

  6. Object Number: 624064  Size: SH
  7. Remove the screws from the HVAC module lower cover.
  8. Remove the auxiliary HVAC module lower cover.

  9. Object Number: 624066  Size: SH
  10. Remove the heater core clamp.
  11. Remove the heater core from the auxiliary HVAC module.
  12. Carefully remove the gasket between the auxiliary HVAC module and the air distributor duct. This gasket will be re-used if possible.

  13. Object Number: 624067  Size: SH
  14. Remove the fasteners and separate the front case half from the back half.
  15. Remove the evaporator core from the back case half.
  16. Inspect the gaskets and the seals for damage.
  17. Replace the gaskets and the seals, as needed.

Installation Procedure


    Object Number: 624067  Size: SH
  1. Install the evaporator core into the case.
  2. Install the evaporator core seal.
  3. Important: Ensure the proper positioning of the air distributor duct gasket and the temperature door during assembly.

  4. Reassemble the case halves.

  5. Object Number: 624066  Size: SH
  6. Install the heater core to the auxiliary HVAC module.
  7. Install the heater core clamp.

  8. Object Number: 624064  Size: SH
  9. Install the auxiliary HVAC module lower cover.
  10. Notice: Refer to Fastener Notice in the Preface section.

  11. Install the screws to the HVAC module lower cover.
  12. Tighten
    Tighten the screws to 1.6 N·m (14 lb in).

  13. Install the heater core pipe retainer and gasket.
  14. Install the stud between the heater core inlet and outlet on the underside of the auxiliary HVAC module.

  15. Object Number: 615126  Size: SH
  16. Install the air temperature actuator (1).

  17. Object Number: 612400  Size: SH
  18. Install the auxiliary HVAC module (3) to the vehicle. Refer to Auxiliary HVAC Module Replacement .