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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1942 (Seat Heating System And Seat Cooling System) >> Diagnostic Information and Procedures >> Heated Seat Inoperative >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2009 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.

Heated Seats Malfunction

  1. Ignition OFF, disconnect the harness connector at the appropriate heated seat switch.
  2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 3 and ground.
    • If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  3. Ignition OFF, connect the harness connector at the heated seat switch and disconnect the harness connector at the appropriate heated seat module.
  4. Test for less than 5 Ω between the ground circuit terminal 5 and ground.
    • If greater than the specified range, test the ground circuit for an open/high resistance.
  5. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 4 and ground.
    • 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 and the HTD/SEAT fuse is open, test the control circuit terminal 3 for a short to ground.
  6. Verify that a test lamp illuminates between the ignition circuit terminal 10 and ground.
    • If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.
  7. Connect a test lamp between the signal circuit terminal 2 and ground.
  8. Press and release the heated seat switch. The test lamp should turn ON and OFF when the switch is pressed and released.
    • If the test lamp is always OFF, test the signal circuit for a short to ground or an open/high resistance. If the circuit test normal test or replace the heated seat switch.
    • If the test lamp is always ON, test the signal circuit for an short to voltage. If the circuit test normal test or replace the heated seat switch.
  9. Ignition OFF, disconnect the X1 harness connector at the seat cushion heater element.
  10. At the male side of the harness connector, test for less than 5 Ω between the ground circuit terminal 2 and ground.
    • If greater than the specified range, test the ground circuit for an open/high resistance.
  11. At the female side of the harness connector, test for infinite resistance between the control circuit terminal 1 and ground.
    • If not the specified value, test the control circuit for a short to ground.
  12. Connect the X1 harness connector at the seat cushion heater element and disconnect the X2 harness connector at the seat back heater element.
  13. Test for 1 - 5 Ω between terminal 1 and terminal 4.
    • If not within the specified range, test or replace the seat back heater element.
  14. Connect the X2 harness connector at the seat back heater element.
  15. At the heated seat module harness connector, test for infinite resistance between the signal circuit terminal 1 and ground.
    • If not the specified value, test the signal circuit for a short to ground.
  16. Ignition ON, verify that a test lamp does not illuminate between the terminals listed below and ground:
    • Heater element control circuit terminal 3
    • Heated seat temperature sensor signal circuit terminal 1
    • If the test lamp illuminates, test the appropriate circuit for a short to voltage.
    17. NOTE: When measuring resistance, the resistance values are based on the seat being at room temperature of 20°C (68°F).
  17. Test for 1.2 k - 30 kΩ between the signal circuit terminal 1 and the low reference circuit terminal 6.
    • If less than the specified range, test for a short between the signal and low reference circuits. If the circuits test normal, test or replace the seat back heater element.
    • If greater than the specified range, test the signal circuit and the low reference circuit for a short to voltage or open/high resistance. If the circuits test normal, test or replace the seat back heater element.
  18. Test for 2 - 5 Ω between the control circuit terminal 3 and the ground circuit terminal 5.
    • If less than the specified range, test for a short between the control and ground circuits. If the circuits test normal, test or replace the seat cushion heater element.
    • If greater than the specified range, test the control circuit and ground circuit for an open/high resistance. If the circuits test normal, test or replace the seat cushion heater element.
  19. If all circuits test normal, replace the heated seat module.

Headed Seat Switch Temperature Indicator Malfunction

  1. Ignition OFF, disconnect the harness connector at the appropriate heated seat switch.
  2. Test for less than 5 Ω between the ground circuit terminal 2 and ground.
    • If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify that a test lamp illuminates between the control circuit terminal 1 and ground.
  4. Ignition OFF, connect the harness connector at the heated seat switch and disconnect the harness connector at the heated seat module.
  5. Ignition ON, connect a test lamp between the control circuit terminals listed below and ground. The appropriate indicator should turn ON and OFF when the test lamp is connected and disconnected.
    • Low control circuit terminal 9
    • Medium control circuit terminal 8
    • High control circuit terminal 7
    • If the indicator is always ON, test the appropriate control circuit for a short to ground. If the circuit tests normal, test or replace the heated seat switch.
    • If the indicator is always OFF, test the appropriate control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, test or replace the heated seat switch.
  6. If all circuits test normal, replace the heated seat module.
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