Hummer H3. Manual — part 1254

to Air Conditioning
(A/C) System
Performance Test .

The discharge line is
hot.

The suction line is cool.

Do the listed conditions exist?

Go to Step 7

Go to Step 6

6

1. Refer to the pressures

recorded during the A/C
system performance test.

2. Inspect for the following

conditions:

The low side pressure is
slightly lower than the
specified pressure
ranges but still within
Zone A on the A/C
Pressure-Zone
Classification Chart in
the A/C System
Performance Test. Refer
to Air Conditioning
(A/C) System
Performance Test .

The discharge line is
warm-to-hot.

The suction line is cool-
to-warm.

Do the listed conditions exist?

-

Go to Step 8

Go to Too Hot
in Vehicle

7

The A/C system may be
undercharged.

1. Leak test A/C system. Refer

to Leak Testing.

2. Recharge the A/C system to

specifications. Refer to

-

2007 Hummer H3

2007 HVAC Heating, Ventilation and Air Conditioning - H3

Refrigerant Recovery and
Recharging.

Is the action complete?

Go to Step 14

-

8

The A/C system may be
contaminated.
View the information screen on J
43600 ACR 2000 Air
Conditioning Service Center for
detection of foreign gases in the
A/C system. See Special Tools.
Do foreign gases exist?

-

Go to Step 9

Go to Step 10

9

1. Evacuate the A/C system to a

scavenging tank. Refer to
Refrigerant Recovery and
Recharging.

2. Recharge the A/C system to

specifications.

Is the action complete?

-

Go to Step 14

-

10

The A/C system may contain too
much moisture or air.

1. Evacuate and recharge the

A/C system to specifications.
Refer to Refrigerant
Recovery and Recharging.

2. Operate the A/C system and

inspect the instrument panel
outlet air temperatures. Refer
to Air Conditioning (A/C)
System Performance Test.

Are the instrument panel outlet air
temperatures within the specified
ranges of the A/C Performance
Test Table?

-

Go to Step 15 Go to Step 11

2007 Hummer H3

2007 HVAC Heating, Ventilation and Air Conditioning - H3

11

The A/C system may contain too
much refrigerant oil.

1. Operate the A/C system with

the engine at idle speed and
the blower speed on low for
approximately 15 minutes.

2. Recover the refrigerant from

the A/C system. Refer to
Refrigerant Recovery and
Recharging.

3. Remove the receiver

dehydrator. Refer to
Receiver Dehydrator
Replacement.

4. Drain and measure the

refrigerant oil from the
receiver dehydrator.

Was more than the specified
amount of refrigerant oil drained
from the receiver?

IMPORTANT:

Operate the A/C system on low,
in order to enhance oil flow to
the high side of the system.

148 ml (5

oz.)

Go to Step 12 Go to Step 13

12

1. Reinstall the receiver

dehydrator. Refer to
Receiver Dehydrator
Replacement.

2. Flush the A/C system. Refer

to Flushing.

3. Recharge the A/C system.

Refer to Refrigerant
Recovery and Recharging.

Are the actions complete?

-

Go to Step 14

-

2007 Hummer H3

2007 HVAC Heating, Ventilation and Air Conditioning - H3

AIR CONDITIONING (A/C) DIAGNOSTICS - PRESSURE ZONE B

Air Conditioning (A/C) Diagnostics - Pressure Zone B

13

1. Add the specified amount of

refrigerant oil to the receiver
dehydrator. Refer to
Refrigerant System
Capacities.

2. Install the receiver

dehydrator. Refer to
Receiver Dehydrator
Replacement.

3. Recharge the A/C system.

Refer to Refrigerant
Recovery and Recharging.

Are the actions complete?

-

Go to Step 14

-

14

1. Record the low and high side

pressures and the instrument
panel outlet air temperature.

2. Compare the instrument panel

outlet air temperatures to
those listed in the A/C System
Performance Chart. Refer to
Air Conditioning (A/C)
System Performance Test.

Are the high and low side pressures
and instrument panel outlet air
temperatures within specifications?

-

Go to Step 15

Go to Air
Conditioning
(A/C) System
Performance
Test

15

Operate the system in order to
verify the repair.
Did you find and correct the
condition?

-

System OK

Go to
Symptoms -
HVAC
Systems -
Manual

Step

Action

Yes

No

DEFINITION: The low side pressure is higher than normal and the high side pressure is

2007 Hummer H3

2007 HVAC Heating, Ventilation and Air Conditioning - H3