Component Testing

Heated and Cooled Seat Switch

1. Ignition OFF, disconnect the X4 harness connector at the appropriate door lock/window switch.
2. Test for infinite resistance between the low reference circuit terminal 4 and the signal terminals listed below the with the switch in the open position.
   • Seat back only mode switch terminal 7
   • Seat back cushion heat switch terminal 6
   • Seat cool switch terminal 3
   • If not the specified value, replace the heated and cooled seat switch.
3. Test for less than 2 Ω between the low reference circuit terminal 4 and the signal terminals listed below with the appropriate switch in the closed position.
   • Seat back only mode switch terminal 7
   • Seat back cushion heat switch terminal 6
   • Seat cool switch terminal 3
   • If greater than the specified range, replace the heated and cooled seat switch.
4. Connect a 3 A fused jumper wire between the low reference circuit terminal 4 and ground.
5. Connect a test lamp between B+ and each control terminal listed below. The appropriate indicator should illuminate.
   • Seat back only mode indicator terminal 11
   • Seat cool mode indicator terminal 12
   • Seat back and cushion indicator terminal 10
   • Low temperature indicator terminal 9
   • Medium temperature indicator terminal 1
   • High temperature indicator terminal 2
   • If any indicator does not illuminate, replace the heated and cooled seat switch.

Ventilation Heat and Cool Module

1. Ignition OFF, disconnect the harness connectors at the seat cushion and seat back ventilation heat and cool modules.
NOTE: 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 Ω ±5 percent. For warmer or cooler 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 Ω.
2. Test for 300 Ω - 18 kΩ 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.
NOTE: 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 conditions listed below 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 warmer or cooler 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 Ω 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.
NOTE: The test leads must be connected in the correct polarity, otherwise higher out of range values will appear. Use the Positive Lead for the control circuit and the Negative Lead for the ground circuit.
4. Test for 6 k - 9 kΩ between blower motor control circuit terminal 2 and the low reference circuit terminal 4.
   • If not within the specified range, replace the ventilation heat and cool module.
NOTE: 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 k - 420 kΩ 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.