Blower Motor Malfunction
| Blower Motor 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 Fault Information |
| Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
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Blower Motor Control Module B+
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B0193 06
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B0193 06
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-
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-
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Blower Motor B+
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1
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1
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-
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-
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Blower Motor Control Module Control
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B0193 06
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B0193 06
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B0193 01
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-
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Blower Motor Controls
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2
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1
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1
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-
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Blower Motor Control Module Ground
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-
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1
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-
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-
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1. Blower Motor Inoperative
2. Blower Motor Always On |
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| Circuit/System Description |
The blower motor control module is an interface between the HVAC control module and the blower motor. The blower motor speed control from the HVAC control module, battery positive and ground circuits enable the blower motor control module to operate. The HVAC control module provides a pulse width modulation (PWM) signal to the blower motor control module in order to command the blower motor speed. The blower motor control module transfers the PWM signal into a corresponding blower motor voltage. The voltage resides between 2-13 V and changes linear to the height of the PWM signal.
| 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 |
| 1. |
Ignition ON, press and release the blower speed increase switch. Verify the scan tool Blower Motor Switch parameter changes between Inactive and Up.
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| 2. |
If not the specified value, replace the A20 Radio/HVAC Controls.
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| 3. |
Press and release the blower speed decrease switch. Verify the scan tool Blower Motor Switch parameter changes between Inactive and Down.
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| 4. |
If not the specified value, replace the A20 Radio/HVAC Controls.
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| 5. |
Press and release the AUTO Switch. Verify the scan tool Auto HVAC Button parameter changes between Active and Inactive.
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| 6. |
If not the specified value, replace the A20 Radio/HVAC Controls.
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| Circuit/System Testing |
| 1. |
Ignition OFF, disconnect the X2 harness connector at the K8 Blower Motor Control Module.
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| 2. |
Verify that a test lamp illuminates between the B+ and ground circuit terminal 5 X2.
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| 3. |
If the test lamp does not illuminate, test the ground circuit for an open circuit/high resistance.
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| 4. |
Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 6 X2 at the K8 Blower Motor Control Module harness connector and ground.
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| 5. |
If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
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| 6. |
Ignition OFF, disconnect the harness connector at the M8 Blower Motor and connect the X1 harness connector at the K8 Blower Motor Control Module.
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| 7. |
Ignition ON, verify that a test lamp illuminates between the M8 Blower Motor B+ circuit terminal 2 and ground.
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| 8. |
If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K8 Blower Motor Control Module.
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| 9. |
Connect a test lamp between the M8 Blower Motor B+ circuit terminal 2 and the M8 Blower Motor control circuit terminal 1.
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| 10. |
Turn the blower motor OFF. Verify the test lamp does not illuminate.
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| 11. |
If the test lamp illuminates, test the control circuit for a short to ground. If the circuit tests normal, replace the K8 Blower Motor Control Module and verify that the test lamp does not always illuminate. If the test lamp always illuminates, replace the K33 HVAC Control Module.
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| 12. |
Turn the blower motor stepwise from low speed to high speed. The test lamp intensity should increase.
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| 13. |
If the test lamp does not illuminate, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K8 Blower Motor Control Module and verify that the test lamp illuminates. If the test lamp does not illuminate, replace the K33 HVAC Control Module.
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| 14. |
If the test lamp intensity does not vary, replace the K8 Blower Motor Control Module and verify that the intensity varies. If the test lamp intensity does not vary, replace the K33 HVAC Control Module.
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| 15. |
If all circuits test normal, replace the K8 Blower Motor Control Module.
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| Repair Instructions |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
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Control Module References
for HVAC control module replacement, setup, and programming
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Heater and Blower and Air Conditioning Control Module Replacement
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Blower Motor Replacement
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Heater and Air Conditioning Control Replacement
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