Vented Seat Malfunction
Vented Seat Malfunction
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.
Circuit/System Description
Battery positive voltage is supplied at all times to the driver seat blower motors from the DPM Fuse located in the left rear fuse block. Battery positive voltage is also supplied at all times to the front passenger seat blower motors from the RF HTD ST/S BAND Fuse located in the right rear fuse block. Both, the driver seat and passenger seat blower motors are grounded through their ground circuits and G307. When a vented seat switch is pressed, the climate control seat module sends a low side pulse width modulation (PWM) signal through the blower motor control circuits to the seat cushion and seat back blower motors indicating the vented seat command. In response to this signal, the logic in the blower motors set the blower speed to the switch set point. Both blower motors then run drawing cabin air around and away from occupant.
Diagnostic Aids
When performing resistance measurements on the heated seat system, make sure the seats are cooled. If the seat heating elements are still warm, resistance readings may be affected.
Reference Information
Schematic Reference
Heated/Cooled Seat Schematics (Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector Views)
Description and Operation
Heated/Vented Seat Description and Operation (Heated/Vented Seat Description and Operation)
Electrical Information Reference
* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)
Scan Tool Reference
Control Module References (Programming and Relearning) for Scan Tool Information
Circuit System Verification
1. Ignition ON, with a scan tool, observe the following vented seat switch parameters while pressing and releasing the related switch. The readings should change between ACTIVE and INACTIVE as each switch is operated.
* Driver Seat Vent Sw.
* Psgr. Seat Vent Sw.
• If the readings do not change as each switch is activated, replace the HVAC control module.
2. Ignition ON, operate both driver and front passenger heated and vented seat functions. Both driver and front passenger heated/vented seats should heat and cool when commanded.
• If both driver and front passenger heated and vented seat functions are inoperative, refer to Front Heated Seat Malfunction (Front Heated Seat Malfunction) .
• If both driver and front passenger vented seats are inoperative, refer to Driver and Front Passenger Vented Seats Malfunction.
• If the driver vented seat is inoperative, refer to Driver Vented Seat Malfunction.
• If the front passenger vented seat is inoperative, refer to Front Passenger Vented Seat Malfunction.
Circuit/System Testing
Driver and Front Passenger Vented Seats Malfunction
1. Ignition OFF, disconnect the X2 harness connector at the CCSM.
2. Ignition OFF, test for less than 5 ohms between the ground circuit terminal 6 and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
3. Ignition ON, verify that a test lamp illuminates between the ignition 3 B+ circuit terminal 3 and ground.
• If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
4. Ignition OFF, disconnect the X1 harness connector at the CCSM.
5. Verify that a test lamp illuminates between the B+ circuit terminal B and ground.
• If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
6. Connect the X1 and X2 harness connectors at the CCSM.
7. Disconnect the harness connectors at the driver and front passenger cushion heated seat elements.
8. Verify that a test lamp illuminates between B+ and the temperature sensor low reference circuit terminal d.
• If the test lamp does not illuminate, test the low reference circuit for a short the voltage or an open/high resistance. If the circuit tests normal, replace the CCSM.
9. If all circuits test normal, replace the CCSM.
Driver Vented Seat Malfunction
1. Ignition OFF, disconnect the X4 harness connector at the MSM.
2. Ignition ON, test for 4.50-5.50 volts between the PWM serial data circuit terminal 1 and ground.
• If less than the specified range, test the serial data circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the CCSM.
• If greater than the specified range, test the serial data circuit for a short to voltage. If the circuit tests normal, replace the CCSM.
3. Ignition OFF, connect the X4 harness connector at the MSM.
4. Disconnect the harness connector at the driver cushion cooled seat blower motor.
5. Ignition OFF, test for less than 5 ohms between the ground circuit terminal B and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
6. Disconnect the harness connector at the driver back cooled seat blower motor.
7. Ignition OFF, test for less than 5 ohms between the ground circuit terminal B and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
8. Ignition ON, test for B+ between the voltage supply circuit terminal C at the driver cushion blower motor and ground.
• If less than the specified range, test the B+ circuit for a short to ground or an open/high resistance.
9. Ignition ON, test for B+ between the voltage supply circuit terminal C at the driver seat back blower motor and ground.
• If less than the specified range, test the B+ circuit for a short to ground or an open/high resistance.
10. Ignition ON, test for 9.8-10.2 volts between the driver cushion blower motor control circuit terminal A and ground.
• If less than the specified value, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the CCSM.
• If greater than the specified value, test the control circuit for a short to voltage. If the circuit tests normal, replace the CCSM.
11. Ignition ON, test for 9.8-10.2 volts between the driver seat back blower motor control circuit terminal A and ground.
• If less than the specified value, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the CCSM.
• If greater than the specified value, test the control circuit for a short to voltage. If the circuit tests normal, replace the CCSM.
12. If all circuits test normal, replace the MSM.
Front Passenger Vented Seat Malfunction
1. Ignition OFF, disconnect the X4 harness connector at the MSM.
2. Ignition ON, test for 4.50-5.50 volts between the PWM serial data circuit terminal 11 and ground.
• If less than the specified range, test the serial data circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the CCSM.
• If greater than the specified range, test the serial data circuit for a short to voltage. If the circuit tests normal, replace the CCSM.
3. Ignition OFF, connect the X4 harness connector at the MSM.
4. Disconnect the harness connector at the passenger cushion cooled seat blower motor.
5. Ignition OFF, test for less than 5 ohms between the ground circuit terminal B and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
6. Disconnect the harness connector at the driver back cooled seat blower motor.
7. Ignition OFF, test for less than 5 ohms between the ground circuit terminal B and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
8. Ignition ON, test for B+ between the voltage supply circuit terminal C at the passenger cushion blower motor and ground.
• If less than the specified range, test the B+ circuit for a short to ground or an open/high resistance.
9. Ignition ON, test for B+ between the voltage supply circuit terminal C at the driver seat back blower motor and ground.
• If less than the specified range, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ fuse is open, replace the CCSM.
10. Ignition ON, test for 9.8-10.2 volts between the passenger cushion blower motor control circuit terminal A and ground.
• If less than the specified value, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the CCSM.
• If greater than the specified value, test the control circuit for a short to voltage. If the circuit tests normal, replace the CCSM.
11. Ignition ON, test for 9.8-10.2 volts between the passenger seat back blower motor control circuit terminal A and ground.
• If less than the specified value, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the CCSM.
• If greater than the specified value, test the control circuit for a short to voltage. If the circuit tests normal, replace the CCSM.
12. If all circuits test normal, replace the MSM.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Driver Seat and Passenger Seat Back Cushion Heater Replacement (Driver Seat and Passenger Seat Back Cushion Heater Replacement)
* Driver Seat and Passenger Seat Cushion Heater Replacement (Driver Seat and Passenger Seat Cushion Heater Replacement)
* Control Module References (Programming and Relearning) for CCSM, HVAC control module, and MSM replacement, setup, and programming