Component Testing

Ventilation Heat and Cool Module

1. Ignition OFF, disconnect the harness connectors at the seat cushion and seat back ventilation heat and cool modules.
   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 . The delta resistance values between the seat cushion and seat back temperature sensors should not be greater than 2000 ohms.
2. Test for 300 ohms-18K ohms of resistance between the temperature sensor signal circuit terminal 5 and the low reference circuit terminal 8.
   • If not within the specified range, replace the ventilation heat and cool module.
   IMPORTANT: The test leads must be connected in the correct polarity, otherwise lower out of range values will appear. Use the Positive Lead for the COOL control circuit and the Negative Lead for the HEAT control circuit. If the resistance is measured with the seat still warm or cool, the resistance values will vary even if the system was powered up for just a few seconds. The TED must be allowed to stabilize to room temperature prior to a measurement. The following conditions will change the resistance to out of range values:

   • The test leads are incorrectly connected.
   • Air blowing across the TED
   • Measuring the resistance at other than room temperature of 70°F
   • Holding the TED portion of the heated and cool ventilation module in your hand

     In hotter or colder climates where room temperature conditions of 70°F (21°C) may be unattainable, resistance values may read above the specified range. Use a heat gun or a blower to warm or cool the TED while measuring the resistance. The resistance values should slowly lower toward the specified range.

3. Test for 0.9-10.0 ohms of resistance between the heat control circuit terminal 1 and the cool control circuit terminal 3.
   • If not within the specified range, replace the ventilation heat and cool module.
     IMPORTANT: The test leads must be connected in the correct polarity, otherwise higher out of range values will appear. Use the Positive Lead for the supply voltage circuit and the Negative Lead for the ground circuit.
4. Test for 6-9K ohms of resistance between blower motor supply voltage circuit terminal 2 and the low reference circuit terminal 4.
   • If not within the specified range, replace the ventilation heat and cool module.
     IMPORTANT: The test leads need to be connected in the correct polarity, otherwise higher out of range values will appear. Use the Positive Lead for the speed control circuit and the Negative Lead for the ground circuit.
5. Test for 290-420K ohms of resistance between blower motor speed control circuit terminal 7 and the low reference circuit terminal 4.
   • If not within the specified range, replace the ventilation heat and cool module.