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Blower Motor Malfunction

Diagnostic Instructions
    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    • Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Blower Motor Control Module B+

B0193 06

B0193 06

--

--

Blower Motor B+

1

1

--

--

Blower Motor Control Module Control

B0193 06

B0193 06

B0193 01

-

Blower Motor Control

2

1

1

-

Blower Motor Control Module Ground

-

B0193 06

--

--

1. Blower Motor Inoperative

2. Blower Motor Always ON

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 amounts to between 2-13 V and changes linear to the reading of the PWM signal.

Diagnostic Aids

Check the following mechanical fault sources:

    • Air distribution box
    • Air distribution hoses/air distribution ducts

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

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

  1. Ignition ON, turn the blower motor knob on high speed then to low speed. Verify the scan tool Blower Motor Switch parameter. The reading should correspond to the selected blower step.
    2. [ARW-LISTFAIL]

  2. If the parameter does not correspond to the selected fan step

    Replace the A26 HVAC Controls.

    3. [/ARW-LISTFAIL][ARW-LISTPASS]

  3. If the parameter corresponds to the selected fan step

    4. [/ARW-LISTPASS]
  4. Ignition OFF, disconnect the X1 harness connector at the K8 Blower Motor Control Module.
  5. Test for less than 5 Ω between the K8 Blower Motor Control Module ground circuit terminal 5 X1 and ground.
    6. [ARW-LISTFAIL]

  6. If greater than 5 Ω

    Repair the open/high resistance in the circuit.

    7. [/ARW-LISTFAIL][ARW-LISTPASS]

  7. If less than 5 Ω

    8. [/ARW-LISTPASS]
  8. Ignition ON, verify that a test lamp illuminates between K8 Blower Motor Control Module the B+ circuit terminal 6 X1 and ground.
    9. [ARW-LISTFAIL]

  9. If the test lamp does not illuminate and the circuit fuse is good

    10. [/ARW-LISTFAIL]
    4.1. Ignition OFF.
    4.2. Test for less than 2 Ω in the B+ circuit end to end.
    [ARW-LISTFAIL]

  10. If 2 Ω or greater, repair the open/high resistance in the circuit.

  11. If less than 2 Ω, verify the fuse is not open and there is voltage at the fuse.

    12. [/ARW-LISTFAIL] [ARW-LISTFAIL]

  12. If the test lamp does not illuminate and the circuit fuse is open

    13. [/ARW-LISTFAIL]
    4.1. Ignition OFF.
    4.2. Test for infinite resistance between the B+ circuit and ground.
    [ARW-LISTFAIL]

  13. If less than infinite resistance, repair the short to ground on the circuit.

    14. [/ARW-LISTFAIL][ARW-LISTPASS]

  14. If infinite resistance

    15. [/ARW-LISTPASS]
    4.3. Disconnect the harness connector at the M8 Blower Motor.
    4.4. Test for infinite resistance between the B+ circuit terminal 1 X2 and earth.
    [ARW-LISTFAIL]

  15. If less than infinite resistance, repair the short to ground on the circuit.

    16. [/ARW-LISTFAIL][ARW-LISTPASS]

  16. If infinite resistance

    17. [/ARW-LISTPASS]
    4.5. Connect the harness connector at the M8 Fan Motor.
    4.6. Install a 40 A fused jumper wire between the B+ circuit terminal 1 X2 and B+ and verify the fuse is good.
    [ARW-LISTFAIL]

  17. If the fuse is open, replace the M8 Fan Motor.

  18. If the fuse is good, replace the K8 Fan Motor Control Module.

    19. [/ARW-LISTFAIL] [ARW-LISTPASS]

  19. If the test lamp illuminates

    20. [/ARW-LISTPASS]
  20. Ignition OFF, disconnect the harness connector at the M8 Blower Motor and connect the X1 harness connector at the K8 Blower Motor Control Module.
  21. Ignition ON, verify that a test lamp illuminates between the M8 Fan Motor B+ circuit terminal A and earth.
    22. [ARW-LISTFAIL]

  22. If the test lamp does not illuminate

    23. [/ARW-LISTFAIL]
    6.1. Ignition OFF.
    6.2. Test for less than 2 Ω in the B+ circuit end to end.
    [ARW-LISTFAIL]

  23. If 2 Ω or greater, repair the open/high resistance in the circuit.

  24. If less than 2 Ω, replace the K8 Blower Motor Control Module.

    25. [/ARW-LISTFAIL] [ARW-LISTPASS]

  25. If the test lamp illuminates

    26. [/ARW-LISTPASS]
  26. Connect a test lamp between the M8 Fan Motor B+ circuit terminal A and the M8 Fan Motor control circuit terminal B.
  27. Turn the blower motor OFF. Verify the test lamp does not illuminate.
    28. [ARW-LISTFAIL]

  28. If the test lamp illuminates

    29. [/ARW-LISTFAIL]
    8.1. Ignition OFF, disconnect the X2 harness connector at the K8 Blower Motor Control Module. Keep the test lamp still connected.
    8.2. Verify the test lamp does not illuminate.
    [ARW-LISTFAIL]

  29. If the test lamp illuminates, repair the short to earth on the circuit.

    30. [/ARW-LISTFAIL][ARW-LISTPASS]

  30. If the test lamp does not illuminate

    31. [/ARW-LISTPASS]
    8.3. Disconnect the X1 harness connector at the K8 Fan Motor Control Module and connect the X2 harness connector at the K8 Fan Motor Control Module.
    8.4. Verify the test lamp does not illuminate.
    [ARW-LISTFAIL]

  31. If the test lamp illuminates, replace the K8 Fan Motor Control Module.

  32. If the test lamp does not illuminate, replace the K33 HVAC Control Module.

    33. [/ARW-LISTFAIL] [ARW-LISTPASS]

  33. If the test lamp does not illuminate

    34. [/ARW-LISTPASS]
  34. Turn the blower motor stepwise from low speed to high speed. The test lamp intensity should increase.
    35. [ARW-LISTFAIL]

  35. If the test lamp does not illuminate

    36. [/ARW-LISTFAIL]
    9.1. Ignition OFF, disconnect the X2 harness connector at the K8 Blower Motor Control Module.
    9.2. Ignition ON, test for less than 0.3 V between the control circuit terminal 2 X2 and earth.
    [ARW-LISTFAIL]

  36. If greater than 0.3 V, repair the short to voltage on the circuit.

    37. [/ARW-LISTFAIL][ARW-LISTPASS]

  37. If less than 0.3 V

    38. [/ARW-LISTPASS]
    9.3. Ignition OFF, test for less than 2 Ω in the control circuit end to end.
    [ARW-LISTFAIL]

  38. If greater than 2 Ω, repair the open/high resistance in the circuit.

    39. [/ARW-LISTFAIL][ARW-LISTPASS]

  39. If less than 2 Ω

    40. [/ARW-LISTPASS]
    9.4. Replace the K8 Fan Motor Control Module.
    9.5. Ignition ON, turn the fan motor ON and verify the test lamp illuminates.
    [ARW-LISTFAIL]

  40. If the test lamp does not illuminate, replace the K33 HVAC Control Module.

  41. If the test lamp illuminates, all OK.

    42. [/ARW-LISTFAIL] [ARW-LISTFAIL]

  42. If the test lamp intensity does not vary

    43. [/ARW-LISTFAIL]
    9.1. Ignition OFF, replace the K8 Fan Motor Control Module. Keep the test lamp still connected.
    9.2. Ignition ON, turn the fan motor stepwise from low speed to high speed. The test lamp intensity should increase.
    [ARW-LISTFAIL]

  43. If the test lamp intensity does not vary, replace the K33 HVAC Control Module.

  44. If the test lamp intensity varies, all OK.

    45. [/ARW-LISTFAIL] [ARW-LISTPASS]

  45. If the test lamp intensity varies

    46. [/ARW-LISTPASS]
  46. Replace the M8 Blower Motor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Blower Motor Control Module Replacement : Left Hand Drive → Right Hand Drive
    •  Heater and Air Conditioning Control Replacement
    •  Blower Motor Replacement : Right Hand Drive → Left Hand Drive
    • Control Module References for HVAC control module replacement, setup, and programming
   


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