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Home >> GMC >> 2003 >> Safari Van Cargo, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 23 (HVAC Systems - Manual) >> Symptom Tests >> Too Cold In Vehicle

Too Cold In Vehicle

WARNING: This page is about a different car, the 2002 GMC Safari and 2002 Chevrolet Astro. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: For circuit reference, see CONNECTOR IDENTIFICATION  and/or WIRING DIAGRAMS  .
NOTE: Definition: The temperature cannot be adjusted, or the heating is insufficient.
  1. Did you review DESCRIPTION & OPERATION and perform the necessary inspections? If so, go to next step. If not, see DESCRIPTION , OPERATION  and TROUBLE SHOOTING  .
  2. Turn ignition on. Place the mode switch in any position except OFF. Place the blower switch in each speed position. Does the blower motor operate at all? If so, go to next step. If not, see BLOWER MOTOR INOPERATIVE .
  3. Does the blower motor operate in each speed position? If so, go to next step. If not, see BLOWER MOTOR MALFUNCTION .
  4. Alternately place the recirculation door between MAX A/C and VENT. Does the recirculation door operate properly? If so, go to next step. If not, see IMPROPER AIR DELIVERY .
  5. Inspect the cooling system for the following conditions:
    • Low coolant level.
    • Loose or worn accessory drive belt.
    • Leaking radiator hose or heater hose.
    • Kinked radiator hose or heater hose.
    • Missing radiator cap pressure seal.
    • Leaking radiator cap.
    Did you find and correct the condition? If so, go to step  18. If not, go to next step.
  6. Start the engine. Place the mode switch in the OFF or HEAT positions. Does the A/C compressor operate? If so, see A/C COMPRESSOR CLUTCH DOES NOT DISENGAGE . If not, go to next step.
  7. Observe the drive shaft of the temperature actuator. Adjust the air temperature switch. Does the temperature actuator drive shaft rotate at all? If so, go to next step. If not, go to step  9.
  8. Inspect the air temperature door and the temperature actuator for the following conditions:
    • Misaligned temperature actuator.
    • Broken or binding linkages or air temperature door.
    • An obstruction that prevents the air temperature door from operating within its full range of motion.
    • Missing seals to the air temperature door.
    • Misaligned seals to the air temperature door.
    Did you find and correct the condition? If so, go to step  18. If not, see HEATER PERFORMANCE TEST  under PERFORMANCE TESTS.
  9. Check the ignition circuit of the temperature actuator for an open or a high resistance. Did you find and correct the condition? If so, go to step  18. If not, go to next step.
  10. Check the temperature actuator ground circuit for an open. Did you find and correct the condition? If so, go to step  18. If not, go to next step.
  11. Check the control signal circuit of the temperature actuator for an open, high resistance, short to ground, or short to voltage. Did you find and correct the condition? If so, go to step  18. If not, go to next step.
    12. NOTE: Ensure that the HVAC control assembly connector is connected during this test in order to avoid misdiagnosis.
  12. Turn ignition on. Measure the voltage from the air temperature door control signal circuit of the temperature actuator to a good ground. Place the air temperature switch from the coldest position to the warmest position. Specified voltage is 12-volts in cold position and 0-volts in hot position. Are the readings as specified and with a smooth transition between cold and hot? If so, go to next step. If not, go to step  15.
  13. Inspect for poor connections at the temperature actuator harness connector. Did you find and correct the condition? If so, go to step  18. If not, go to next step.
  14. Inspect the temperature actuator, door and any attaching linkage for binding or a condition that prevents drive shaft rotation. Did you find and correct the condition? If so, go to step  18. If not, go to step  16.
  15. Inspect the HVAC control assembly for poor harness connections. Did you find and correct the condition? If so, go to step  18. If not, go to step  17.
  16. Replace the temperature actuator. See TEMPERATURE DOOR ACTUATOR  under REMOVAL & INSTALLATION. After repairs are complete, go to step  18.
  17. Replace the HVAC control assembly. See HVAC CONTROL ASSEMBLY . After repairs, go to next step.
  18. Operate the system in order to verify the repair. If system operates normally, repair is complete. If system still malfunctions, return to step  2.
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