Hummer H1 (2006+). Manual — part 326

11-38 Heating/Ventilation/Air Conditioning (HVAC)

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9.

Remove the fastener from the passenger side closeout panel.

10. Lower the panel down to gain access to the floor outlet hose, remove the screw securing the hose and remove the closeout panel.

11. Remove the two screws securing the passenger side of the auxiliary heat/cool unit. Raise the cover up approximately 2" and

support with a block of wood.

12. Remove the passenger side door strap bracket and the seat belt buckle assembly.

13. Remove the front passenger seat and the right front inner and outer kick panels.

NOTE: Panels are removed to prevent damage that would occur during HVAC unit removal.

14. Note the HVAC harness positioning prior to removal/disconnect.

15. Disconnect the vacuum motor harness, engine HVAC harness, water valve harness, temperature blend door connector, cycling

switch connections, power mirror harness, resistor harness, power door lock harness, power window harness and the blower
motor connections (Figure 11-29).

Figure 11-29: Harness/Connector Identification

16. Pull the harnesses clear of the HVAC unit and secure.

17. Remove the screw(s) securing the floor duct to the top of the HVAC unit. Disconnect the hose going to the passenger floor

area and remove the hose.

18. Remove the two screws, the Christmas tree fastener and remove the transition assembly.

19. Remove the bolt securing the HVAC manifold block to the expansion valve and discard the sealing gasket. Cap all the

openings.

20. Remove the two interior bolts securing the left and the right side of the HVAC unit to the body. Support the unit prior to

removing the second fastener to prevent the unit from falling down and causing possible damage or injury (Figure 11-30).

21. Removal of the unit can be accomplished by lowering and pulling straight rearward.

Installation

Lift the HVAC unit into the vehicle.

1.

Set the lower bracket on the HVAC unit on top of the lower body bracket. Ensure that the studs on the pass through plate align
with the holes in the body. Harnesses must be positioned to exit to the right side of the HVAC unit.

2.

Pivot the unit upwards until it rests against the defrost and floor ducts. Install the right side fastener, two nuts, washers and
grommets on the passthrough plate. Slowly tighten the front pass through mounts first. This action will pull the unit forward.
Ensure that the defrost and heating ducts align properly with the outlets on the HVAC unit before tightening inside mounts.

POWER MIRROR

ENGINE HVAC

VACUUM

RELAYS

RESISTOR

TEMP BLEND

DOOR MOTOR

BLOWER MOTOR

CYCLING

SWITCH

POWER LOCKS

AND WINDOWS

7-S11-062

CONTROL

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Heating/Ventilation/Air Conditioning (HVAC) 11-39

Figure 11-30: Interior mounting points

NOTE: The HVAC unit should have a 1/2” inch spacer between the left side bracket and the body. If the spacer was not present
when the unit was removed, it should be installed when the unit is taken out of the vehicle for service.

3.

Install the left hand interior fastener with the 1/2”spacer, it may be necessary to loosen the bracket and slide it left or right to
align the hole. Tighten the fastener (Figure 11-31).

Figure 11-31: Left Side Mount and Spacer

4.

Install the screw(s) securing the drivers floor duct to the main HVAC unit.

5.

Install the passenger side floor duct and route to the right as previously removed.

6.

Install the transition assembly with the two screws and a new christmas tree fastener.

CAUTION: Be sure to remove all of the devices used to plug the openings in the heater lines and the A/C lines.

7.

Install the manifold block to the expansion valve using a new sealing gasket, torque the fastener to 25 lb-ft.

8.

Install the heater core extension tubes onto the passthrough plate using the new sealing washers. Torque the fasteners to 32 in
lbs.

9.

Evacuate the A/C system for 45 minutes, with a 10 minute hold time for a leak check.

10. Refill the cooling system.

NOTE: When refilling, use bleeder screws on the engine and the radiator to purge as much air as possible from the system. The
bleeder screws also allow easier filling of the cooling system.

11. Charge the A/C system to 2lbs 4oz. Add 2oz. oil if the unit is new or the evaporator was replaced.

12. Leak check the passthrough plate for body leaks using a water hose. If leakage is noted inside the vehicle, seal the leaks from

the outside using body sealer in small amounts.

13. Leak check the A/C lines using a R134-A leak detector.

14. If no leaks are found, install the air cleaner housing, elbow, adapter, rain cap and the air cleaner splash shield.

15. Connect the vacuum control harness, cycling switch connections, power mirror harness, door lock harness, power window

harness, blower motor connections, resistor harness, engine HVAC harness, temperature blend door connector and the water
valve harness.

LEFT SIDE

MOUNT

RIGHT SIDE

MOUNT

1/2” SPACER

LEFT SIDE HVAC UNIT MOUNT

7-S11-067

11-40 Heating/Ventilation/Air Conditioning (HVAC)

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16. Install the center console and check the operation of the A/C and the heat.

17. If the A/C and the heat are functioning properly, install the left front and the right front passenger side kick panels, door strap

and the seat belt buckle assembly.

18. Install the right front seat and the crash pad.

19. Install the right side closeout panel.

VACUUM DOOR MOTOR

Removal

1.

Remove the right front crash pad.

2.

Locate and remove the two screws securing the vacuum motor cover to the main HVAC unit.

3.

Locate the faulty vacuum motor and remove the vacuum line. If multiple motors are to be replaced, tag the vacuum lines as
they are removed.

4.

Note the position of the mounting studs on the motor to be replaced. Mark the holes that the studs pass through (Figure
11-32).

Figure 11-32: Vacuum Door Motor Replacement

5.

Note the position of the motor arm relative to the door lever. Mark the side facing away from the HVAC unit.

6.

Remove the outer push clip with side cutting pliers and discard.

7.

Remove the washer under the push clip, do not discard.

8.

Remove the two mounting nuts and the vacuum motor (Figure 11-32).

PUSH CLIP

MOUNTING NUTS

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Heating/Ventilation/Air Conditioning (HVAC) 11-41

Installation

1.

Secure the vacuum motor with the two mounting nuts.

2.

Slide the motor arm on the door lever and secure with the washer and a new push clip.

3.

Install the vacuum lines.

4.

Secure the motor cover with the two screws.

5.

Install the right front crash pad.

BLEND DOOR MOTOR

Removal

1.

Disconnect the motor electrical connection.

2.

Remove the three nuts securing the motor to the bracket (Figure 11-33).

Figure 11-33: Temperature Blend Door Motor Removal

NOTE: Do not loosen the set screw on the door shaft adapter!

3.

Remove the motor by pulling it straight off. Do not discard the spacers behind the motor.

Installation

1.

Install the blend door motor spacers and door shaft adapter.

2.

Install the blend door motor and secure with the three nuts.

3.

Connect the motor electrical connection.

Heater Core Removal

NOTE: Screws should be noted for length as they are removed to aid in correct reassembly. Some screw lengths are critical to pre-
vent interference with interior parts.

NOTE: Most of the screws used are threaded into the plastic housing of the HVAC unit. Care should be used to prevent over-tight-
ening of the hardware and stripping the holes out.

1.

Remove the HVAC unit from the vehicle (Refer to section 11).

2.

Set the HVAC unit on a bench so the rubber heater hoses are visible and facing upwards.

3.

Remove the protective cover and fully expose the rubber heater hoses .

NOTE: Foam tape and permagum tape should always be replaced with new material where it was removed from during disassem-
bly. The tapes are used to insulate hot and cold parts and prevent condensation from dripping on the passenger floor.

4.

Remove the constant tension clamps from the heater hoses at the heater core (Figure 11-34).

TEMPERATURE BLEND

DOOR MOTOR

NUT

SPACER

DOOR SHAFT ADAPTER

MOUNTING PLATE

7-P11-002