Circuit/System Testing
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2008 GMC Yukon XL, 2008 GMC Yukon, 2008 Chevrolet Tahoe, 2008 Chevrolet Suburban, and 2008 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.
B2425 0A, B2425 0B, B2425 0C, B2425 0D, B2425 0E, B2425 04, or B2425 1F
- Ignition OFF, disconnect the X1 harness connector at the HSM.
- Test for 2.0-8.0 ohms between control circuit terminal 6 and control circuit terminal 5.
- 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.
- Disconnect the X2, X4 harness connectors at the HSM.
- Test for 850-300K ohms between the signal circuit terminal 9 X4 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.
- Connect the X1, X2, X4 harness connectors at the HSM.
- Disconnect the harness connector at the seat cushion heater element/temperature sensor.
- 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 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.
- If all circuits test normal, replace the HSM.
IMPORTANT:
When measuring the resistance, the resistance values are based on the seat being at room temperature of 20°C (68°F).
B2430 0A, B2430 0B, B2430 0C, B2430 0D, B2430 0E, B2430 04, or B2430 1F
- Ignition OFF, disconnect the X1 harness connector at the HSM.
- Test for 2.0-8.0 ohms between control circuit terminal 3 and control circuit terminal 2.
- 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.
- Disconnect the X2, X4 harness connectors at the HSM.
- Test for 850-300K ohms between the signal circuit terminal 20 X4 and the low reference circuit terminal 8 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.
- Connect the X1, X2, X4 harness connectors at the HSM.
- Disconnect the harness connector at the seat cushion heater element/temperature sensor.
- 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 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.
- If all circuits test normal, replace the HSM.
IMPORTANT:
When measuring the resistance, the resistance values are based on the seat being at room temperature of 20°C (68°F).