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Test M: Too Cold In Vehicle

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  1. Perform SYSTEM OPERATION CHECK  under TROUBLE SHOOTING. Go to next step.
  2. Turn ignition on. Place the blower motor switch in each speed position. Does the blower operate in any of the speed positions? If so, go to next step. If not, go to TEST F: BLOWER MOTOR INOPERATIVE .
  3. Does the blower actuator operate correctly for each speed position? If so, go to next step. If not, go to TEST H: BLOWER MOTOR MALFUNCTION .
    4. NOTE: The HVAC control assembly is inoperative when the module does not respond to an operator control request.
  4. Is the HVAC control assembly inoperative? If so, go to step  17. If not, go to next step.
  5. Inspect the cooling system for:
    • Low coolant level.
    • Loose or worn accessory drive belt.
    • Leaking radiator hoses or leaking heater hoses.
    • Kinked radiator hoses or kinked heater hoses.
    • Missing radiator cap pressure seal.
    • Leaking radiator cap.
    Did you find and correct the condition? If so, go to step  24. If not, go to next step.
  6. Start the engine. Place the blower motor switch in the OFF position. Place the A/C request switch in the OFF position. Does the A/C compressor operate? If so, go to TEST J: COMPRESSOR CLUTCH DOES NOT DISENGAGE . If not, go to next step.
  7. Turn ignition on. Observe the drive shaft of the air temperature door actuator. Adjust the air temperature switch. Does the drive shaft of the air temperature door actuator ever rotate? If so, go to next step. If not, go to step  9.
    8. NOTE: If no condition found with all conditions listed then compare door travel to known good vehicle.
  8. Inspect the air temperature door and the air temperature door actuator for:
    • Misaligned actuator on the air temperature door.
    • Broken linkages or binding linkages.
    • Broken air temperature door or a binding air temperature door.
    • Obstruction that prevents the air temperature door from operating within the full range of motion.
    • Missing seals to the air temperature door and misaligned seals to the air temperature door.
    Did you find and correct the condition? If so, go to step  24. If not, go to HEATING SYSTEM PERFORMANCE  under PERFORMANCE TESTS.
  9. Check the air temperature actuator ignition 3 voltage circuit for an open or for a high resistance. Did you find and correct the condition? If so, go to step  24. If not, go to next step.
  10. Check the air temperature actuator ground circuit for an open. Did you find and correct the condition? If so, go to step  24. If not, go to next step.
  11. Check the air temperature actuator 5-volt reference circuit for a high resistance. Did you find and correct the condition? If so, go to step  24. If not, go to next step.
  12. Check the air temperature actuator signal circuit for a high resistance. Did you find and correct the condition? If so, go to step  24. If not, go to next step.
  13. Check the air temperature actuator control circuit for a high resistance. Did you find and correct the condition? If so, go to step  24. If not, go to next step.
    14. NOTE: The voltage will vary between zero-5 volts during normal operation. Ensure to observe the air temperature actuator driveshaft and the volt meter when jumping the control circuit with 5 volt reference and the ground circuits. The air temperature actuator and the HVAC control assembly connectors must be connected during this step.
    NOTE: Ensure the air temperature actuator connector and the HVAC control assembly connector are connected during this step in order to avoid misdiagnosis.
  14. Turn ignition on. Backprobe and monitor the voltage from the signal circuit of the air temperature door actuator to ground. Connect a 3-ampere fused jumper between the control circuit and the 5-volt reference circuit of the air temperature door actuator. This drives the actuator to the full cool mode. Remove and reconnect the jumper wire between the air temperature door control and the ground circuit of the air temperature actuator. This drives the actuator to the full hot mode. Does the drive shaft of the air temperature door actuator rotate and does the voltage change? If so, go to next step. If not, go to step  19.
    15. NOTE: Ensure the air temperature actuator connector is connected during this step in order to avoid misdiagnosis.
  15. Backprobe the connector terminal to the air temperature actuator in order to measure the voltage from the control circuit to ground. Adjust the air temperature switch. Is the voltage measurement near zero volts for increasing, 2.5 volts for decreasing or 2.5 volts for stationary? If so, go to next step. If not, go to step  21.
  16. Inspect the air temperature door for a mechanical condition or for a condition that allows excessive travel of the door. After repairs are complete, go to step  24.
  17. Check the HVAC controller ignition 3 voltage circuit for an open, for a high resistance, or for a short to ground. Did you find and correct the condition? If so, go to step  24. If not, go to next step.
  18. Check the HVAC controller ground circuit for an open. Did you find and correct the condition? If so, go to step  24. If not, go to step  21.
  19. Inspect air temperature actuator harness connector for poor connections. Did you find and correct the condition? If so, go to step  24. If not, go to next step.
  20. Inspect the air temperature actuator, the door, and any attaching linkage, for binding or for a condition that prevents drive shaft rotation. Did you find and correct the condition? If so, go to step  24. If not, go to step  22.
  21. Inspect HVAC control assembly harness connector for poor connections. Did you find and correct the condition? If so, go to step  24. If not, go to step  23.
    22. NOTE: Perform the calibration procedure for the air temperature actuator.
  22. Replace the air temperature door actuator. See AIR TEMPERATURE ACTUATOR  under REMOVAL & INSTALLATION. After repairs are complete, go to step  24.
  23. Replace the HVAC control assembly. See HVAC CONTROL ASSEMBLY  under REMOVAL & INSTALLATION. After repairs are complete, go to next step.
  24. 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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