PRE-RELEASE
HVAC System Malfunction
| HVAC System Malfunction |
| Diagnostic Instructions |
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Perform the
Diagnostic System Check - Vehicle
prior to using this diagnostic procedure.
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Review
Strategy Based Diagnosis
for an overview of the diagnostic approach.
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Diagnostic Procedure Instructions
provides an overview of each diagnostic category.
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| Diagnostic Aids |
Check the following mechanical fault sources:
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Air distribution box
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Air distribution hoses/air distribution ducts
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| Reference Information |
Schematic Reference
HVAC Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Automatic HVAC Description and Operation
Electrical Information Reference
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Circuit Testing
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Connector Repairs
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Testing for Intermittent Conditions and Poor Connections
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Wiring Repairs
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Scan Tool Reference
Control Module References for scan tool information
| Circuit/System Verification |
| Note | ||
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Check for bulletins before proceeding. |
| 1. |
Ignition ON, place the blower motor switch in each speed position. Verify that the blower motor operates properly in each position.
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| 2. |
If the blower motor does not operate properly in all speeds, refer to
DTC B0193
.
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| 3. |
Ignition ON, place the auxiliary blower motor switch in each speed position. Verify that the auxiliary blower motor operates properly in each position.
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| 4. |
If the auxiliary blower motor does not operate properly in all speeds, refer to
DTC B0208
.
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| 5. |
Using the scan tool observe the mode, temperature, air inlet and recirculation door positions. Verify the actual and commanded door positions are within 4 counts of each other.
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| 6. |
If not within the specified range, refer to Circuit/System Testing
DTC B0223, B022A, B0233, B023A, B0408, B0418, B0428, or B3531
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| 7. |
Engine ON, A/C ON, place the temperature control in the coldest position. Verify that cool air flows from the ducts in the vehicle.
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| 8. |
If the air is not cool, refer to
Air Conditioning (A/C) System Performance Test
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| 9. |
Turn the A/C OFF and place the temperature control in the warmest position.
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| 10. |
If the air is insufficiently heated refer to
Heating Performance Diagnostic
.
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| 11. |
Engine OFF, ignition ON, cover the sunload sensor assembly with a shop towel or other suitable item. Verify the scan tool Sunload Sensor parameter changes.
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| 12. |
If it does not change, refer to Circuit/System Testing
DTC B0163, B0183, or B1405
.
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| 13. |
Measure actual inside air temperature using a thermometer. Compare this value to the scan tool Inside Passenger Compartment Air Temp. Sensor parameter. The measured temperature should be within 5 degrees of parameter.
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| 14. |
If not within the specified range, refer to Circuit/System Testing
DTC B0163, B0183, or B1405
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| 15. |
Measure actual temperature using a thermometer at each of the duct temperature sensors. Compare this value to the appropriate scan tool Duct parameter. The measured temperature should be within 5 degrees of appropriate Duct Temperature Sensor parameter.
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| 16. |
If not within the specified range, refer to Circuit/System Testing
DTC B0173, B0178, B0509, B0514, B0519, B3583, or B3933
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| 17. |
Ignition ON, observe the scan tool A/C Evaporator Temperature Sensor parameter. The reading should be between -39°F (-35°C) and 185°F (85°C) and change with evaporator air temperature changes.
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| 18. |
If not within the specified range, refer to Circuit/System Testing
DTC B0173, B0178, B0509, B0514, B0519, B3583, or B3933
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| Repair Instructions |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
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HVAC Component Replacement Reference
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Control Module References
for HVAC control module replacement, setup, and programming
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