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Home >> Hummer >> 2008 >> H2 4D Utility Wagon >> Repair and Diagnosis >> External Pages >> Different car >> Section 207 (Seat Heating System & Seat Cooling System) >> Diagnostic Information and Procedures >> DTC B2425 or B2430 (With Memory, Without HP2) >> Circuit/System Testing

Circuit/System Testing

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B2425 0A, B2425 0B, B2425 0C, B2425 0D, B2425 0E, B2425 04, or B2425 1F

  1. Ignition OFF, disconnect the X3 harness connector at the MSM.
  2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 5 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 X3 harness connector at the MSM and disconnect the X1 harness connector at the MSM.
    4. IMPORTANT: When measuring the resistance, the resistance values are based on the seat being at room temperature of 20°C (68°F).
  4. Test for 2.0-8.0 ohms between control circuit terminal 14 and control circuit terminal 11.
    • If greater than the specified range, test the control circuits for an open/high resistance. If the circuits test normal replace the seat cushion heater element.
    • If less than the specified range, test for a short between the control circuits. If the circuits test normal, replace the seat cushion heater element.
  5. Disconnect the X2, X5 harness connectors at the MSM.
  6. Test for 850-300K ohms between the signal circuit terminal 1 X5 and the low reference circuit terminal 3 X2.
    • 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 cushion heater element/temperature sensor.
    • 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 cushion heater element/temperature sensor.
  7. Connect the X1, X2, X5 harness connectors at the MSM.
  8. Disconnect the harness connector at the seat cushion heater element/temperature sensor.
  9. Ignition ON, test for 4.8-5.2 volts 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 MSM.
    • 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 MSM.
  10. If all circuits test normal, replace the MSM.

B2430 0A, B2430 0B, B2430 0C, B2430 0D, B2430 0E, B2430 04, or B2430 1F

  1. Ignition OFF, disconnect the X3 harness connector at the MSM.
  2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 5 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 X3 harness connector at the MSM and disconnect the X1, X4 harness connectors at the MSM.
    4. IMPORTANT: When measuring the resistance, the resistance values are based on the seat being at room temperature of 20°C (68°F).
  4. Test for 2.0-8.0 ohms between control circuit terminal 6 X1 and control circuit terminal 14 X4.
    • If greater than the specified range, test the control circuits for an open/high resistance. If the circuits test normal replace the seat cushion heater element.
    • If less than the specified range, test for a short between the control circuits. If the circuits test normal, replace the seat cushion heater element.
  5. Disconnect the X2, X5 harness connectors at the MSM.
  6. Test for 850-300K ohms between the signal circuit terminal 2 X5 and the low reference circuit terminal 6 X2.
    • 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 cushion heater element/temperature sensor.
    • 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 cushion heater element/temperature sensor.
  7. Connect the X1, X2, X4, X5 harness connectors at the MSM.
  8. Disconnect the harness connector at the seat cushion heater element/temperature sensor.
  9. Ignition ON, test for 4.8-5.2 volts 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 MSM.
    • 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 MSM.
  10. If all circuits test normal, replace the MSM.
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