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Chevrolet Silverado / GMC Sierra. Manual - part 2307
Conditioning Accumulator Replacement
(Non-HP2).
Is the repair complete?
Go to Step 19
-
19
Install the suction and the discharge lines. Refer
to Suction Hose Replacement (LY2, LMF,
L76 and L92) or Suction Hose Replacement
(LMM) and Discharge Hose Replacement
(LY2, LMF, L76 and L92) or Discharge
Hose Replacement (LMM).
Are the repairs complete?
Go to Step 21
-
20
1. Install the suction and the discharge lines.
Refer to Suction Hose Replacement
(LY2, LMF, L76 and L92) or Suction
Hose Replacement (LMM) and
Discharge Hose Replacement (LY2,
LMF, L76 and L92) or Discharge Hose
Replacement (LMM).
2. Recharge the A/C system. Refer to
Refrigerant Recovery and Recharging.
Are the repairs complete?
Go to Step 21
-
21
1. Record the low and the high side pressures
and the panel outlet air temperature after
you perform the repairs.
2. Compare the pressures and the panel 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 as
shown on the A/C Performance Chart?
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
2008 Chevrolet Silverado 1500
2008 HVAC Heating, Ventilation, and Air Conditioning - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &
Silverado
HEATING PERFORMANCE DIAGNOSTIC
Go to Step 22
w/Engine Driven
Fan)
22
Operate the system in order to verify the repair.
Did you find and correct the condition?
System OK
Go to Symptoms
- HVAC Systems
- Manual
or
Go to Symptoms
- HVAC Systems
- Automatic
Step
Action
Yes
No
1
Were you sent here from Symptoms or another
diagnostic table?
Go to Step 2
Go to Symptoms
- HVAC
Systems -
Manual
or
Go to Symptoms
- HVAC
Systems -
Automatic
2
1. Start the engine.
2. Allow the engine to idle.
Does the engine reach a normal operating
temperature?
Go to Step 3
Go to Step 9
3
1. Allow the engine to idle.
2. Select the FLOOR mode.
3. Select the minimum blower speed.
4. Select the warmest temperature setting.
5. Feel the temperature of the inlet and outlet
heater hoses at the heater core.
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
Does the inlet heater hose feel warmer than the
outlet heater hose?
Go to Step 7
Go to Step 4
4
1. Install a thermometer into the center IP
PANEL air outlet.
2. Secure a thermometer to the heater core
outlet hose.
3. Select the PANEL mode.
4. Select the maximum blower speed.
5. Select the warmest temperature setting.
6. Record the temperature at the following
locations:
The center IP PANEL air outlet
The heater core outlet hose
7. Compare the recorded temperatures.
Are the two temperature readings about equal?
Go to Step 5
Go to Step 6
5
1. Inspect and repair the following areas of
the vehicle for cold air leaks:
The cowl
The recirculation door
The HVAC module case
2. Perform the necessary repairs.
Are the repairs complete?
Go to Step 10
-
6
1. Inspect the temperature door operation.
Refer to Diagnostic System Check -
Vehicle .
2. Perform any necessary repairs.
Are the repairs complete?
Go to Step 10
-
1. Turn OFF the engine.
2. Backflush the heater core.
3. Start the engine.
4. Select the FLOOR mode.
2008 Chevrolet Silverado 1500
2008 HVAC Heating, Ventilation, and Air Conditioning - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &
Silverado
DEFROSTING INSUFFICIENT
7
5. Select the minimum blower speed.
6. Select the warmest temperature setting.
7. Feel the temperature of the inlet and outlet
heater hoses at the heater core.
Does the inlet heater hose feel warmer than the
outlet heater hose?
Go to Step 8
Go to Step 10
8
Replace the heater core. Refer to Heater Core
Replacement.
Is the repair complete?
Go to Step 10
-
9
Repair the low engine temperature concern.
Refer to Engine Fails To Reach Normal
Operating Temperature .
Is the repair complete?
Go to Step 10
-
10
Operate the system in order to verify the repair.
Did you find and correct the condition?
System OK
Go to Step 2
Step
Action
Yes
No
1
Were you sent here from Symptoms or another
diagnostic table?
Go to Step 2
Go to Symptoms
- HVAC
Systems -
Manual
or
Go to Symptoms
- HVAC
Systems -
Automatic
2
1. Start the engine.
2. Select the DEFROST mode.
3. Select the maximum blower speed.
Does sufficient air flow from the defroster
outlets?
Go to Step 3
Go to Step 10
3
Measure the engine operating temperature.
Does engine reach a normal operating
2008 Chevrolet Silverado 1500
2008 HVAC Heating, Ventilation, and Air Conditioning - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &
Silverado
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