GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2009 🢒 Yukon Denali 🢒 HVAC 🢒 Heating, Ventilation, and Air Conditioning 🢒 Auxiliary Heater Pipe Replacement

Removal Procedure

    Object Number: 12777 Size: SH
  1. Drain the cooling system. Refer to Cooling System Draining and Filling.
  2. Squeeze the plastic retainer tabs on the inlet hose.

    3. Object Number: 12778 Size: SH
  3. Pull the connection apart.

    4. Object Number: 12777 Size: SH
  4. Squeeze the plastic retainer tabs on the outlet hose.

    5. Object Number: 12778 Size: SH
  5. Pull the connection apart.

    6. Object Number: 612571 Size: SH
  6. Remove the auxiliary heater pipes (1, 2) from the heater inlet and outlet tees (3, 4) at the HVAC module.
  7. Remove the vehicle right assist step. Refer to Assist Step Replacement.

    8. Remove both of the right tires. Refer to Tire and Wheel Removal and Installation.

  8. Remove the right rear wheelhouse panel. Refer to Rear Wheelhouse Panel Liner Replacement.
  9. Remove the right front wheelhouse panel. Refer to Front Wheelhouse Liner Replacement - Right Side.

    10. Object Number: 612548 Size: SH
  10. Remove the auxiliary heater pipes (2, 3) from the auxiliary heater core.

    11. Object Number: 691870 Size: SH
  11. Remove the heater/A/C tubes retaining nut (4) from the stud (1) at the frame (6).
  12. Remove the auxiliary heater pipes (2) from the clamps (5).
  13. Remove the auxiliary heater pipes from the vehicle.

Installation Procedure

Note: The replacement A/C and heater pipes are shipped in two sections and spliced together upon installation. Refer to Auxiliary Heater and Air Conditioning Pipe Repair.

  1. Install the auxiliary heater pipes to the vehicle.

    2. Object Number: 691870 Size: SH
  2. Install the auxiliary heater pipes (2) to the clamps (5).

    3. Caution: Refer to Fastener Caution in the Preface section.

  3. Install the heater/A/C tubes retaining nut (4) to the stud (1) at the frame (6) and tighten to 7 N·m (62 lb in).

    4. Object Number: 612548 Size: SH
  4. Install the auxiliary heater pipes (2, 3) to the auxiliary heater core.
  5. Install the right front wheelhouse panel. Refer to Front Wheelhouse Liner Replacement - Right Side.
  6. Install the right rear wheelhouse panel. Refer to Rear Wheelhouse Panel Liner Replacement.
  7. Install the vehicle right assist step. Refer to Assist Step Replacement.

    8. Object Number: 612571 Size: SH
  8. Install the auxiliary heater pipes (1, 2) to the heater inlet and outlet tees (3, 4).

    9. Object Number: 21855 Size: SH
  9. Connect the outlet heater hose to the heater core.
  10. Connect the inlet heater hose to the heater core.
  11. Fill the cooling system. Refer to Cooling System Draining and Filling.