Tahoe 2WD V8-6.0L Hybrid (2008)
11. Connect a test lamp between the following circuits and ground. The test lamp should illuminate or slowly illuminate for approximately 5 seconds
after pressing the HEAT switch.
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Terminal 2 seat cushion blower motor supply voltage
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Terminal 7 seat cushion blower motor speed control
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If the test lamp does not illuminate, test the appropriate circuit for an open/high resistance. If the circuit tests normal, replace the CCSM.
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If the test lamp is always ON, test the appropriate circuit for a short to voltage. If the circuit tests normal, replace the CCSM.
12. Connect the harness connector to the seat cushion heat/cool seat ventilation blower.
13. Disconnect the harness connector at the seat back heat/cool seat ventilation blower.
14. Ignition OFF, test for less than 5 ohms of resistance between the blower motor low reference circuit terminal 4 and ground.
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If greater than 5 ohms, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the CCSM.
15. Ignition ON, test for 4.8-5.2 volts between the temperature sensor signal circuit terminal 5 and ground.
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If greater than 5.2 volts, test the signal circuit for a short to voltage. If the circuit tests normal, replace the CCSM.
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If less than 4.8 volts, replace the CCSM.
Important: The ignition must be cycled OFF then ON between each test in order to reset the CCSM.
16. Ignition ON, connect a test lamp between the following control circuits and ground. The test lamp should illuminate or slowly illuminate for
approximately 4 seconds after the switch is pressed. On the heat control circuit, the test lamp may exhibit a 4 second delay before it starts to
illuminate.
Press the HEAT switch for heat control and the COOL switch for cool control.
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Terminal 1 seat back heat control circuit
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Terminal 3 seat back cool control circuit
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If the test lamp does not illuminate, replace the CCSM.
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If the test lamp is always ON, test the appropriate control circuit for a short to voltage. If the circuit tests normal, replace the CCSM.
Important: The ignition must be cycled OFF then ON between each test in order to reset the CCSM.
17. Connect a test lamp between the following circuits and ground. The test lamp should illuminate or slowly illuminate for approximately 5 seconds
after pressing the HEAT switch.
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Terminal 2 seat back blower motor supply voltage circuit
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Terminal 7 seat cushion blower motor speed control
^
If the test lamp does not illuminate, test the appropriate circuit for an open/high resistance. If the circuit tests normal, replace the CCSM.
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If the test lamp is always ON, test the appropriate circuit for a short to voltage. If the circuit tests normal, replace the CCSM.
18. If all circuits test normal, test or replace the appropriate heat/cool seat ventilation blower.
Passenger Heated/Cool Seat Circuit Test
1. Ignition OFF, disconnect the X1, X2, X3 harness connectors at the CCSM.
2. Connect a test lamp between the heated/cooled seat mode signal circuit terminal 6 X3 and battery voltage.
3. Press the HEAT or COOL switch through the high, medium, and low positions to OFF. The test lamp should illuminate until the OFF position is
reached.
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If the test lamp does not illuminate, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace
the MSM.
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If the test lamp is ON with the switch in the OFF position, test the signal circuit for a short to ground. If the circuit tests normal, replace the
MSM.
Important: If the resistance is measured with the seat still warm or cool, the resistance values will vary. At 68°F (20°C), the nominal
resistance value is 1200 ohms ±5 percent. For hotter or colder ambient temperatures, refer to the Temperature vs Resistance table below.
The delta resistance values between the seat cushion and seat back temperature sensors should not be greater than 2000 ohms.
