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Home >> GMC >> 2006 >> Sierra 1500 HD, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1007 (Seat Heating System & Seat Cooling System) >> Diagnostic Information and Procedures >> DTC B1935 or B2180 >> Circuit/System Testing

Circuit/System Testing

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B1935

  1. Ignition OFF, disconnect the X1 harness connector at the MSM.
  2. Test for less than 15 ohms between the heater element supply voltage circuit terminal 14 and the control circuit terminal 1.
    • If greater than the specified range, test the supply voltage circuit and the control circuit for an open/high resistance. If the circuits test normal, replace the seat back heating element.
  3. Disconnect the X2, X5 harness connectors at the MSM.
  4. Test for 850-300k ohms between the temperature sensor signal circuit terminal 4 X5 and the low reference circuit terminal 2 X2.
    • If greater than the specified range, test the signal circuit and low reference circuit for a short to voltage or an open/high resistance. If the circuits test normal, replace the seat back heating element.
    • 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.
  5. Connect the X1, X2, X5 harness connectors at the MSM.
  6. Disconnect the harness connector at the seat back heater element.
  7. Ignition ON, test for 4.8-5.2 volts between the temperature sensor 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 voltage. If the circuit tests normal, replace the MSM.
  8. If all circuits test normal, replace the MSM.

B2180

  1. Ignition OFF, disconnect the X1 harness connector at the MSM.
  2. Test for less than 15 ohms between the heater element supply voltage circuit terminal 6 and the control circuit terminal 4.
    • If greater than the specified range, test the supply voltage circuit and the control circuit for an open/high resistance. If the circuits test normal, replace the seat back heating element.
  3. Disconnect the X2, X5 harness connectors at the MSM.
  4. Test for 850-300k ohms between the temperature sensor signal circuit terminal 3 X5 and the low reference circuit terminal 5 X2.
    • If greater than the specified range, test the signal circuit and low reference circuit for a short to voltage or an open/high resistance. If the circuits test normal, replace the seat back heating element.
    • 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 heating element.
  5. Connect the X1, X2, X5 harness connectors at the MSM.
  6. Disconnect the harness connector at the seat back heating element.
  7. Ignition ON, test for 4.8-5.2 volts between the temperature sensor 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 voltage. If the circuit tests normal, replace the MSM.
  8. If all circuits test normal, replace the MSM.
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