Vented Seat Malfunction
Vented Seat Malfunction
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
Diagnostic Fault Information
Circuit/System Description
The driver and front passenger vented seats are controlled by separate vented seat switches located in the radio/HVAC controls. When a vented seat switch is pressed, a serial data message is sent from the radio/HVAC controls to the seat heating control module indicating the vented seat command. In response to this message, the seat heating control module applies a low side pulse width modulation (PWM) signal through the seat vent motor control circuit to the seat temperature control module indicating the vented seat command. In response to this signal, the temperature control module sends a high side pulse width modulation (PWM) signal through the seat blower motor control circuits to the seat back and cushion blower motors indicating the vented seat command. The logic in the blower motors set the blower speed to the switch set point. The seat ventilation blower motors run, drawing cabin air around and away from occupant.
Reference Information
Schematic Reference
Heated/Cooled Seat Schematics Electrical Diagrams
Connector End View Reference
Component Connector End Views Fuel Pump and Level Sensor Assembly
Description and Operation
Heated/Vented Seat Description and Operation Heated/Vented Seat
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
Scan Tool Reference
Control Module References Control Module References for scan tool information
Circuit/System Verification
1. Ignition ON.
2. Verify the heated seat system operates.
• If the heated seat system does not operate
Refer to Front Heated Seat Malfunction (KA1 With KU1 and KU3) Front Heated Seat Malfunction (KA1 With KU1 and KU3)Front Heated Seat Malfunction (KA1 Without KU1 and KU3) Front Heated Seat Malfunction (KA1 Without KU1 and KU3)
• If the heated seat system operates
3. Verify the appropriate scan tool Body Control Module vented seat switch parameter listed below changes between Inactive and Active when pressing the vented seat switch.
* Driver Seat Ventilation Switch
* Passenger Seat Ventilation Switch
• If the parameter does not change
Replace the A20 radio/HVAC controls.
• If the parameter changes
4. Verify the seat cushion and seat back blower motors turn ON and OFF.
• If either or both the seat cushion and seat back blower motors are inoperative
Refer to Circuit/System Testing
• If the blower motors do not change speed or are always ON
Refer to Circuit/System Testing
• If the seat cushion and seat back blower motors operate
5. All OK.
Circuit/System Testing
1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the appropriate K54 Seat Temperature Control Module. It may take up to 2 minutes for all vehicle systems to power down.
2. Test for less than 10 ohms between the ground circuit terminal 3 and ground.
• If 10 ohms or greater
1. Ignition OFF.
2. Test for less than 2 ohms in the ground circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, repair the open/high resistance in the ground connection.
• If less than 10 ohms
3. Ignition ON.
4. Verify a test lamp illuminates between the ignition circuit terminal 5 and ground.
• If the test lamp does not illuminate and the circuit fuse is good
1. Ignition OFF.
2. Test for less than 2 ohms in the ignition circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse.
• If the test lamp does not illuminate and the circuit fuse is open
1. Ignition OFF.
2. Test for infinite resistance between the ignition circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, replace the K54 Seat Temperature Control Module.
• If the test lamp illuminates
5. Connect a test lamp between the control circuit terminal 4 and B+.
6. Verify the test lamp turns ON when pressing the vented seat switch through the High, Medium, and Low positions and the test lamp turns OFF when the OFF position is reached.
• If the test lamp does not turn ON
1. Ignition OFF, disconnect the harness connector at the K29F Seat Heating Control Module - Front, ignition ON.
2. Test for less than 1 V between the control circuit and ground
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V
3. Test for less than 2 ohms in the control circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K29F Seat Heating Control Module - Front.
• If the test lamp does not turn OFF
1. Ignition OFF, disconnect the harness connector at the K29F Seat Heating Control Module - Front.
2. Test for infinite resistance between the control circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, replace the K29F Seat Heating Control Module - Front.
• If the test lamp turns ON and OFF
7. Ignition OFF, connect the harness connector at the K54 Seat Temperature Control Module and disconnect the harness connector at the M73 Seat Blower Motor - Back.
8. Test for less than 10 ohms between the low reference circuit terminal 6 and ground.
• If 10 ohms or greater
1. Ignition OFF, disconnect the harness connector at the K54 Seat Temperature Control Module.
2. Test for less than 2 ohms in the low reference circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K54 Seat Temperature Control Module.
• If less than 10 ohms
9. Connect a test lamp between the ignition circuit terminal 3 and ground, ignition ON.
10. Verify the test lamp turns ON when pressing the vented seat switch through the High, Medium, and Low blower speed positions then OFF when the OFF position is reached.
• If the test lamp is always OFF
1. Ignition OFF, remove the test lamp, disconnect the harness connector at the K54 Seat Temperature Control Module.
2. Test for infinite resistance between the ignition circuit and ground.
• if less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance
3. Test for less than 2 ohms in the ignition circuit end to end.
• If 2 ohms or greater, repair the open high/resistance in the ignition circuit.
• If less than 2 ohms, replace the K54 Seat Temperature Control Module.
• If the test lamp is always ON
1. Ignition OFF, remove the test lamp, disconnect the harness connector at the K54 Seat Temperature Control Module, ignition ON.
2. Test for less than 1 V between the ignition circuit and ground.
• if 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the K54 Seat Temperature Control Module.
• If the test lamp turns ON and OFF
11. Connect a DMM between each control circuit terminal listed below and ground, one at a time.
* Terminal 4
* Terminal 5
12. Test for 2-5 V when pressing the vented seat switch through the High, Medium, and Low positions.
• If less than 2 V
1. Ignition OFF, disconnect the harness connector at the K54 Seat Temperature Control Module.
2. Test for infinite resistance between the control circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance
3. Test for less than 2 ohms in the control circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K54 Seat Temperature Control Module.
• If greater than 5 V
1. Ignition OFF, disconnect the harness connector at the K54 Seat Temperature Control Module, ignition ON.
2. Test for less than 1 V between the control circuit and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the K54 Seat Temperature Control Module.
• If between 2-5 V
13. Replace the M73 Seat Blower Motor - Back.
14. Connect all system components, ignition ON.
15. Verify both seat cushion and seat back blower motors operate.
• If either one or both are inoperative
Replace the M73 Seat Blower Motor - Cushion.
• If both seat cushion and seat back blower motors operate
16. All OK.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Front Seat Vent Fan Mat Replacement Front Seat Vent Fan Mat Replacement
* Front Seat Back Cushion Vent Fan Mat Replacement Front Seat Back Cushion Vent Fan Mat Replacement
* Control Module References Control Module References for K29F Seat Heating Control Module - Front, A20 Radio/HVAC Controls, and K54 Seat Temperature Control Module replacement, programming and setup