Hummer H3. Manual — part 1257

Are the temperatures of these components
only mildly warm?

Go to Step 14

Go to Step 8

7

1. Recover the refrigerant. Refer to

Refrigerant Recovery and
Recharging.

2. Remove the restriction from the

component or replace the component
which produced an abrupt
temperature drop.

Is the action complete?

Go to Step 9

-

8

1. Recover the refrigerant and evacuate

the system. Refer to Refrigerant
Recovery and Recharging.

2. Record the weight of the recovered

refrigerant.

3. Compare the weight of the recovered

refrigerant with the system capacity.
Refer to Refrigerant System
Capacities.

Is the weight of the recovered refrigerant
charge greater than 75% of the total system
capacity?

Go to Step 9

Go to Step 10

9

Recharge the A/C system. Refer to
Refrigerant Recovery and Recharging.
Is the cooling performance improved?

Go to Step 21

Go to Step 10

10

1. Leak test the system. Refer to Leak

Testing.

2. Repair any leaks.

Is the action complete?

Go to Step 21

-

The expansion device is restricted.

1. Replace the expansion device. Refer

to Thermal Expansion Valve
Replacement (Left Hand Drive) or

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2007 HVAC Heating, Ventilation and Air Conditioning - H3

11

Thermal Expansion Valve
Replacement (Right Hand Drive).

2. If the expansion device was

restricted, note the type of debris
present.

Are metal flakes present?

Go to Step 12

Go to Step 13

12

1. Remove the suction line from the

vehicle. Refer to Suction Hose
Replacement (Left Hand Drive) or
Suction Hose Replacement (Right
Hand Drive).

2. Inspect the hose for debris by

blowing shop air through one end of
the hose while covering the other end
with a shop towel.

3. Observe the amount of debris

collected in the shop towel.

Did a large amount of debris collect in the
shop towel?

Go to Step 18

Go to Step 20

13

If the expansion device was restricted with
a brown or black residue, perform the
following procedure:

1. Flush the A/C system. Refer to

Flushing.

2. Replace the receiver dehydrator.

Refer to Receiver Dehydrator
Replacement.

Are the actions complete?

Go to Step 21

-

1. Recover the refrigerant. Refer to

Refrigerant Recovery and
Recharging.

2. Disconnect the suction and the

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2007 HVAC Heating, Ventilation and Air Conditioning - H3

14

discharge lines from the compressor.
Refer to Suction Hose Replacement
(Left Hand Drive) or Suction Hose
Replacement (Right Hand Drive)
and to Discharge Hose
Replacement.

3. Inspect for the presence of debris in

the compressor suction port.

Is debris present in the compressor suction
port?

Go to Step 15

Go to Step 19

15

1. Remove the debris from the suction

port.

2. Inspect the expansion device for

damage or debris. Refer to Thermal
Expansion Valve Replacement
(Left Hand Drive) or Thermal
Expansion Valve Replacement
(Right Hand Drive).

Did you find evidence of damage or
debris?

Go to Step 17

Go to Step 16

16

If the expansion device does not show any
signs of damage or debris, perform the
following procedure:

1. Remove the suction line from the

vehicle. Refer to Suction Hose
Replacement (Left Hand Drive) or
Suction Hose Replacement (Right
Hand Drive).

2. Inspect the hose for debris by

blowing shop air through one end of
the hose while covering the other end
with a shop towel.

3. Observe the amount of debris

collected in the shop towel.

2007 Hummer H3

2007 HVAC Heating, Ventilation and Air Conditioning - H3

Did a large amount of debris collect in the
shop towel?

Go to Step 18

Go to Step 19

17

1. Replace the expansion device. Refer

to Thermal Expansion Valve
Replacement (Left Hand Drive) or
Thermal Expansion Valve
Replacement (Right Hand Drive).

2. If the expansion device was

restricted, observe the type of debris
present.

Are metal flakes present?

Go to Step 12

Go to Step 13

18

If a large amount of debris was collected in
the shop towel from the suction hose,
replace the receiver dehydrator. Refer to
Receiver Dehydrator Replacement.
Is the action complete?

Go to Step 19

-

19

Install the suction and the discharge lines.
Refer to Suction Hose Replacement
(Left Hand Drive) or Suction Hose
Replacement (Right Hand Drive) and
Discharge Hose Replacement.
Is the action complete?

Go to Step 21

-

20

1. Install the suction and the discharge

lines. Refer to Suction Hose
Replacement (Left Hand Drive) or
Suction Hose Replacement (Right
Hand Drive) and to Discharge Hose
Replacement.

2. Recharge the A/C system. Refer to

Refrigerant Recovery and
Recharging.

Are the actions complete?

Go to Step 21

-

1. Record the low and the high side

pressures and the instrument panel
outlet air temperature after you

2007 Hummer H3

2007 HVAC Heating, Ventilation and Air Conditioning - H3