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Home >> Hummer >> 2008 >> H2 4D Utility Wagon >> Repair and Diagnosis >> External Pages >> Different car >> Section 470 (Seat Heating System And Seat Cooling System) >> Diagnostic Information and Procedures >> DTC B1935 or B2180 (Dealer Installed) >> Circuit/System Testing

Circuit/System Testing

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B1935 0A, B1935 0B, B1935 0C, B1935 0D, B1935 0E, B1935 04, or B1935 1F

  1. Ignition OFF, disconnect the X1 harness connector at the HSM.
    2. IMPORTANT:

    Element resistance must be measured twice to ensure that all failure conditions are simulated. First with the seat unoccupied, then with the seat occupied.

  2. Test for 3.5 - 11.5 Ω between control circuit terminal 3 and control circuit terminal 1.
    • If less than the specified range, test for a short between the control circuits. If the circuits test normal, replace the seat back heater element.
    • If greater than the specified range, test the control circuits for an open/high resistance. If the circuits test normal, replace the seat back heater element.
  3. Disconnect the X2, X4 harness connectors at the HSM.
  4. Test for 850 Ω - 300 kΩ between the signal circuit terminal 19 X4 and the low reference circuit terminal 5 X2.
    • If less than the specified range, test for a short between the signal and low reference circuits. If the circuits test normal, replace the seat back heater element/temperature sensor.
    • If greater than the specified range, test the signal and low reference circuits for a short to voltage or an open/high resistance. If the circuits test normal, replace the seat back heater element/temperature sensor.
  5. Connect the X1, X2, X4 harness connectors at the HSM.
  6. Disconnect the harness connector at the seat back heater element/temperature sensor.
  7. Ignition ON, test for 4.8 - 5.2 V between the signal circuit terminal C and ground.
    • If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the HSM.
    • If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the HSM.
  8. If all circuits test normal, replace the HSM.

B2180 0A, B2180 0B, B2180 0C, B2180 0D, B2180 0E, B2180 04, or B2180 1F

  1. Ignition OFF, disconnect the X1 harness connector at the HSM.
    2. IMPORTANT:

    Element resistance must be measured twice to ensure that all failure conditions are simulated. First with the seat unoccupied, then with the seat occupied.

  2. Test for 3.5 - 11.5 Ω between control circuit terminal 6 and control circuit terminal 4.
    • If less than the specified range, test for a short between the control circuits. If the circuits test normal, replace the seat back heater element.
    • If greater than the specified range, test the control circuits for an open/high resistance. If the circuits test normal, replace the seat back heater element.
  3. Disconnect the X2, X4 harness connectors at the HSM.
  4. Test for 850 Ω - 300 kΩ between the signal circuit terminal 10 X4 and the low reference circuit terminal 7 X2.
    • If less than the specified range, test for a short between the signal and low reference circuits. If the circuits test normal, replace the seat back heater element/temperature sensor.
    • If greater than the specified range, test the signal and low reference circuits for a short to voltage or an open/high resistance. If the circuits test normal, replace the seat back heater element/temperature sensor.
  5. Connect the X1, X2, X4 harness connectors at the HSM.
  6. Disconnect the harness connector at the seat back heater element/temperature sensor.
  7. Ignition ON, test for 4.8 - 5.2 V between the signal circuit terminal C and ground.
    • If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the HSM.
    • If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the HSM.
  8. If all circuits test normal, replace the HSM.
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