Chevrolet Silverado / GMC Sierra. Service manual — part 2305

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

Conditioning Accumulator
Replacement (Non-HP2).

5. Evacuate and recharge the A/C system.

Refer to Refrigerant Recovery and
Recharging.

Is the repair complete?

Go to Step 13

-

12

1. Replace the A/C compressor. Refer to Air

Conditioning Compressor
Replacement (LY2, LY5, LH6, L76,
L92 and LMG) or Air Conditioning
Compressor Replacement
(LLY/LMM) or Air Conditioning
Compressor Replacement (LU3).

2. Evacuate and recharge the A/C system.

Refer to Refrigerant Recovery and
Recharging.

Is the repair complete?

Go to Step 13

-

13

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

System OK

Go to Symptoms
- HVAC Systems
- Automatic

Step

Action

Yes

No

DEFINITION: The low and the high side pressures are both higher than normal.

Restricted Condenser Air Flow

Cooling Fan Malfunction

Expansion Device Malfunction

Were you sent here from the A/C System
Performance Test?

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

2008 Chevrolet Silverado 1500

2008 HVAC Heating, Ventilation, and Air Conditioning - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &

Silverado

1

Go to Step 2

(A/C) System
Performance
Test (Gas
Engine w/
Electric Cooling
Fan) or Air
Conditioning
(A/C) System
Performance
Test (Gas
Engine
w/Engine Driven
Fan)

2

1. With the engine idling, turn ON the A/C.

2. Inspect for proper cooling fan operation.

Refer to Cooling System Description
and Operation .

Are the cooling fans ON and operating
properly?

Go to Step 3

Go to Step 5

3

Visually inspect for the following:

Restricted air flow.

Damaged condenser cooling fins.

Inspect for missing or misaligned air
baffles.

Do the following conditions exist?

Go to Step 4

Go to Step 6

4

Repair the air flow restriction.
Is the repair complete?

Go to Step 9

-

5

Repair the cooling fan operation fault. Refer to
Fan Clutch Diagnosis .
Is the repair complete?

Go to Step 9

-

6

Feel the liquid line on both sides of the

CAUTION:

Refer to Moving Parts and Hot Surfaces Caution .

2008 Chevrolet Silverado 1500

2008 HVAC Heating, Ventilation, and Air Conditioning - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &

Silverado

expansion device.Is the temperature the same
before and after the expansion device?

Go to Step 7

Go to Step 8

7

Replace the damaged/faulty orifice tube. Refer
to Expansion (Orifice) Tube Replacement.
Is the repair complete?

Go to Step 9

-

8

Air is in the refrigerant system, or the system is
overcharged. Refer to the view screen on the J
43600 ACR 2000 Refrigerant Station for
foreign gas content in the refrigerant. See
Special Tools.
Recover and recharge the A/C system. Refer to
Refrigerant Recovery and Recharging.
Is the repair complete?

Go to Step 9

-

9

1. Record the low and high side pressures

and the I/P outlet air temperature after
repairs are performed.

2. Compare the pressures and outlet

temperature to those listed in the A/C
Performance Chart. Refer to Air
Conditioning (A/C) System
Performance Test (Diesel Engine) or
Air Conditioning (A/C) System
Performance Test (Gas Engine w/
Electric Cooling Fan) or Air
Conditioning (A/C) System
Performance Test (Gas Engine
w/Engine Driven Fan).

Are the readings within the specified ranges?

Go to Step 10

Go to Air
Conditioning
(A/C) System
Performance
Test (Diesel
Engine) or Air
Conditioning
(A/C) System
Performance
Test (Gas
Engine w/
Electric Cooling
Fan) or Air
Conditioning
(A/C) System
Performance
Test (Gas
Engine
w/Engine Driven
Fan)

10

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

Go to Symptoms
- HVAC Systems
- Manual
or
Go to Symptoms
- HVAC Systems

2008 Chevrolet Silverado 1500

2008 HVAC Heating, Ventilation, and Air Conditioning - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &

Silverado

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

System OK

- Automatic

Step

Action

Yes

No

DEFINITION: The low side pressure is lower than normal and the high side pressure is
higher than normal.
A restriction in the A/C system.

1

Were you sent here from the A/C System
Performance Test?

Go to Step 2

Go to Air
Conditioning
(A/C) System
Performance
Test (Diesel
Engine) or Air
Conditioning
(A/C) System
Performance
Test (Gas
Engine w/
Electric Cooling
Fan) or Air
Conditioning
(A/C) System
Performance
Test (Gas
Engine
w/Engine Driven
Fan)

2

Feel the liquid line before the expansion
device.Is the liquid line cold before the
expansion device?

CAUTION:

Refer to Moving Parts and Hot Surfaces Caution .

Go to Step 3

Go to Step 8

Feel along the surfaces of the following high
side components:

The compressor discharge hose

The condenser

2008 Chevrolet Silverado 1500

2008 HVAC Heating, Ventilation, and Air Conditioning - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &

Silverado