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Hummer H1 (2002+). Manual - part 191

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Heating/Ventilation/Air Conditioning (HVAC) 11-43

05745159

EVAPORATOR

Replacement

Remove HVAC unit from vehicle (refer to HVAC unit
replacement).

Remove heater core from main unit (refer to heater core
replacement).

Remove lower support bracket from HVAC case
(Figure 11-72).

Figure 11-72: Lower Support Bracket Removal

Disconnect vacuum harness from vacuum motors. Motors
are color coded to vacuum tubing (Figure 11-72).

Figure 11-73: Vacuum Door Motor Harness

Remove air intake housing from main unit by removing
attaching screws at blower housing (Figure 11-75) and
bracket at front of unit (Figure 11-74).

Figure 11-74: Air Intake Box Front Bracket Removal

Figure 11-75: Lower Blower Housing Hardware

Removal

Remove face duct outlet plenum (Figure 11-76).

Figure 11-76: Face Duct Outlet Plenum

Remove floor door travel limiting rivet by drilling head,
note the side of the rivet the door is resting on
(Figure 11-77).

NOTE: Place a reference mark on the case to ensure that the
rivet is placed in the same location during reassembly that it
was removed from (Figure 11-77).

Figure 11-77: Drilling Door Travel Limiting Rivet

7-S11-042

BRN

BLU

YEL

GRY

ORG

BLK

WHT

RED

VACUUM DOOR MOTOR HARNESS

7-S11-051

7-S11-052

7-S11-043

FACE OUTLET PLENUM

7-S11-059

REFERENCE MARK

DEFROST OUTLET

FLOOR OUTLET

7-S11-041

11-44

Heating/Ventilation/Air Conditioning (HVAC)

______________________

Remove arm retaining push clip, arm and 2 washers from
the floor door and defrost door (Figure 11-78).

Figure 11-78: Push Clip Removal

Remove defrost motor from the bracket, note position of
mounting studs in mounting plate (Figure 11-79).

Figure 11-79: Vacuum Door Motor Mounting Plate

10. Remove arm retaining push nuts and washers from

remaining vacuum motors.

11. Remove screws securing vacuum motor mounting plate to

main HVAC unit, and remove mounting plate. If the floor
door travel limiting rivet was not removed, the door arm
will prevent removal of the mounting plate by not aligning
with the elongated slot (Figure 11-79).

12. Remove screws securing case halves together. Do not

attempt to separate case at this time (Figure 11-80).

13. Remove screws securing thermostatic cycling switch to

HVAC unit case (Figure 11-80).

CAUTION: Do not attempt to pull the switch out of the case,
the capillary tube is secured to the evaporator.

14. Using a utility knife, carefully cut through the sealer

between the two case halves. Use caution to prevent
cutting the case.

Figure 11-80: Case Half Hardware Removal

15. Using a putty knife or scraper, carefully spread apart the

entire case seam.

16. Separate case halves. Note that the thermostatic cycling

switch must stay with the case half containing the evaporator.

17. Remove permagum tape from around liquid and vapor

tubes, discard.

18. Remove expansion valve from the passthrough plate,

discard gasket (Figure 11-81).

Figure 11-81: Expansion Valve Removal

PUSH CLIP

DEFROST DOOR MOTOR

FLOOR DOOR MOTOR

7-S11-040

7-S11-046

DEFROST DOOR MOTOR

VACUUM DOOR
MOUNTING PLATE

7-S11-048

SCREW

S-CLIP

THERMOSTATIC CYCLING SWITCH

EXPANSION VALVE

7-S11-044

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Heating/Ventilation/Air Conditioning (HVAC) 11-45

05745159

19. Remove screws securing passthrough plate support

bracket to the main unit (Figure 1-82).

Figure 1-82: Passthrough Plate Support Removal

20. Remove bolt securing passthrough plate to the evaporator

manifold connection, remove plate and support bracket.

21. Remove evaporator from unit (Figure 1-83).

22. Carefully remove capillary tube from evaporator, noting

positioning in the evaporator fins (Figure 1-83).

Figure 1-83: Evaporator Removal

23. Disconnect evaporator extension tubes at the O-ring

fittings (Figure 1-84). Discard the O-rings.

Figure 1-84: Evaporator Extension Tubes Removal

Installation

Obtain new evaporator. Ensure that any foam tape found on
the previously removed unit is duplicated on the replacement.

Install extension tubes onto new evaporator using new o-
rings lubricated with refrigerant oil.

Install evaporator into the case half the previous
evaporator was removed from

Position thermostat capillary tube in the same location it was
removed from on the original evaporator. I will be necessary
to hot glue the tube near the exit hole (Figure 1-83).

Install second half of HVAC unit, ensuring that the edges
of the case halves engage the S clips around the seam.

Install screws securing the two halves together.

Install screws securing cycling switch to the side of the
HVAC case.

Using neutral cure silicone sealer, seal entire parameter of seam.

Install the passthrough plate onto the main unit and
evaporator. Install bolt securing evaporator extension tubes
to the passthrough plate. Use a new sealing washer between
the passthrough plate and the evaporator extension tubes.

NOTE:

It may be necessary to trim the middle from the gasket

as received. The normal span of the gasket will not fit the evap-
orator extension tube span.

10. Install expansion valve with a new sealing washer and

torque to 100 in lbs.

11. Install Vacuum motor bracket onto main unit
12. Install defrost door motor onto mounting plate.
13. Connect all vacuum motors to their perspective door arms

using washers and new push clips.

14. Install a new door travel limiting rivet into case, placing the

door on the side of the rivet it was originally resting on.

15. Install face duct plenum.
16. Install air intake assembly onto the main case.
17. Install lower support bracket.
18. Install heater core and retaining brackets, using new

sealing washers on the heater core tubes. Torque heater
manifold to 32 in lbs.

19. Install vacuum harness onto vacuum motors.
20. Install unit into vehicle (refer to HVAC unit removal and

installation).

21. Fill the cooling system.
22. Evacuate A/C system for minimum of 45 minutes, with a

10 minute hold time for leak check. Recharge with 3 lbs
2oz , adding same amount of oil that was drained from the
original evaporator.

Cycling Switch Replacement

Refer to evaporator replacement.

Air Intake Assembly Replacement

Refer to evaporator replacement.

7-S11-050

7-S11-060

THERMOSTATIC CYCLING SWITCH

HOT GLUE

7-S11-045

EXTENSION TUBES

EVAPORATOR

7-S11-045

11-46

Heating/Ventilation/Air Conditioning (HVAC)

______________________

REAR CONSOLE REPLACEMENT

Removal

Remove two screw/washers securing rear console to side
brackets (Figure 1-85).

Push console rearward so that the vents are clear from the
plenum cutouts.

Remove rear console.

Installation

Position rear console over the auxiliary HVAC unit so that
the console vents line up with the plenum cutouts.

Push console forward until vents fit into plenum.

Secure rear console to side brackets with screw/washers
(Figure 1-85).

Figure 1-85: Rear Console Installation

AUXILIARY AIR CONDITIONING/HEATING
UNIT REPLACEMENT

Removal

Discharge air conditioning system.

Remove rear console (Section 10).

Remove heater hoses from auxiliary unit heater core ports
(Figure 1-87).

Remove pressure hoses from auxiliary unit.

Remove drain tubes from auxiliary unit (Figure 1-87).

Figure 1-86: Auxiliary A/C Components

Figure 1-87: Auxiliary Heater Hose Routing

Remove screws securing side brackets to tunnel mounting
bracket.

Remove auxiliary unit from vehicle.

Installation

Install auxiliary unit in vehicle and secure side brackets to
tunnel mounting bracket with screws (Figure 1-86).

Install drain tubes on auxiliary unit (Figure 1-87).

Install pressure hoses on auxiliary unit.

Wrap low pressure fitting with prestite tape.

Secure heater hoses to heater core ports on auxiliary unit
with worm gear clamps. Remove hose pinch pliers.

Evacuate, charge, and leak test air conditioning system.

Check engine coolant level and add coolant as necessary.

Start engine and operate auxiliary and front air
conditioning system to check for proper operation.

Check coolant connections for leakage; repair if
necessary.

10. Stop engine, recheck coolant level, and add coolant if

necessary.

11. Install rear console (Section 10).

00-S11-006

REAR

VENTS

SIDE

BRACKET

PLENUM

SCREW/WASHER

CONSOLE

PLENUM CUTOUT

MOUNTING

SMALL

LARGE

O-RING

AUXILIARY UNIT

BRACKET

SELF-TAPPING

SCREW

A/C HOSE

DRAIN

TUBES

HEATER

CORE

PORTS

CLAMP

HEATER

HOSES

DRAIN TUBES

AND TEE

4-1-00

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