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Test A: Air Delivery Improper

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NOTE: For circuit reference, see CONNECTOR IDENTIFICATION  and/or WIRING DIAGRAMS  .
  1. Perform SYSTEM OPERATION CHECK  under TROUBLE SHOOTING. Go to next step.
  2. Turn ignition on. Place the blower control in the OFF position. Is the blower motor OFF? If so, go to next step. If not, go to TEST D: BLOWER MOTOR ALWAYS ON 
    3. NOTE: This step tests for a blower motor that does not operate regardless of the desired blower motor speed.
  3. Place the blower control in each speed position. Does the blower motor operate at all? If so, go to next step. If not, go to TEST F: BLOWER MOTOR INOPERATIVE .
    4. NOTE: This step tests for a blower motor that operates, yet does not accurately respond to the desired blower motor speed.
  4. Does the blower motor operate correctly for each speed position? If so, go to next step. If not, go to TEST H: BLOWER MOTOR MALFUNCTION .
    5. NOTE: This step verifies that there is power to the HVAC control assembly.
  5. Is the HVAC control assembly inoperative in all positions? If so, go to next step. If not, go to step  16.
  6. Observe the mode actuator drive shaft. Place the mode control in each mode position. Does the mode actuator drive shaft rotate for each selected position? If so, go to next step. If not, go to step  8.
  7. Inspect the mode door and the mode actuator for incorrectly installed mode actuator, broken or binding linkages or mode door and obstruction that prevents the mode door from operating within its full range of motion. Did you find and correct the condition? If so, go to step  23. If not, check for intermittent and poor connections.
  8. Check the mode actuator ignition 3 voltage circuit for an open or a high resistance. Did you find and correct the condition? If so, go to step  23. If not, go to next step.
  9. Check the mode actuator ground circuit for an open. Did you find and correct the condition? If so, go to step  23. If not, go to next step.
  10. Check the mode actuator 5 volt reference circuit for an open, a high resistance, short to ground, or a short to voltage. Did you find and correct the condition? If so, go to step  23. If not, go to next step.
  11. Check the mode actuator mode door position signal circuit for an open, a high resistance, short to ground, or a short to voltage. Did you find and correct the condition? If so, go to step  23. If not, go to next step.
  12. Check the mode actuator mode door control circuit for an open, a high resistance, short to ground, or a short to voltage. Did you find and correct the condition? If so, go to step  23. If not, go to next step.
    13. NOTE: The mode actuator connector and the HVAC controller connector must be connected to correctly perform the test.
  13. Turn ignition on. Backprobe and monitor the voltage from the mode door position signal circuit of the mode actuator ground. Connect a 3 amp fused jumper wire between the mode door control circuit and the 5 volt reference circuit of the mode actuator (drives the motor to FLR). Remove and reconnect the jumper wire between the mode door control circuit and the ground circuit of the mode actuator (drives the motor to DEF). Does the mode actuator drive shaft rotate and does the voltage change? If so, go to next step. If not, go to step  18.
  14. Backprobe the mode actuator connector terminal in order to measure the voltage from the mode door control circuit to ground. Place the mode control in each mode position. Does the voltage measure near zero when airflow moves toward DEF, near 5 volts when airflow moves toward FLR, and near 2.5 volts when stationary? If so, go to next step. If not, go to step  20.
  15. Inspect the mode door for a mechanical failure or a condition that allows excessive travel to the door. After repairs are complete, go to step  23.
  16. Check the HVAC controller ignition 3 voltage circuit for an open, a high resistance or a short to ground. Did you find and correct the condition? If so, go to step  23. If not, go to next step.
  17. Check the HVAC controller ground circuit for an open. Did you find and correct the condition? If so, go to step  23. If not, go to step  20.
  18. Inspect the mode actuator harness connector for poor connections. Did you find and correct the condition? If so, go to step  23. If not, go to next step.
  19. Inspect the mode door and any attaching linkage for any binding. Inspect the duct work for any debris that would prevent air flow through the duct work. Did you find and correct the condition? If so, go to step  23. If not, go to step  21.
  20. Inspect the HVAC control assembly harness connector for poor connections. Did you find and correct the condition? If so, go to step  23. If not, go to step  22.
  21. Replace the mode actuator. See MODE ACTUATOR  under REMOVAL & INSTALLATION. After repairs are complete, go to  23.
  22. Replace the HVAC control assembly. See HVAC CONTROL ASSEMBLY  under REMOVAL & INSTALLATION. After repairs are complete, go to next step.
  23. Operate the system in order to verify the repair. Did you correct the condition? If so, system is okay. If not, go to step  2.
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