Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Ignition Voltage | 1, 4 | 1, 4 | -- | -- |
Ignition Voltage - Driver Seat Back Blower Motor | 1, 4 | 2 | -- | -- |
Ignition Voltage - Driver Seat Cushion Blower Motor | 1, 4 | 3 | -- | -- |
Driver Vented Seat Signal | 1 | 1 | 1 | -- |
Driver Seat Back Blower Motor Ground | -- | 2 | -- | -- |
Driver Seat Cushion Blower Motor Ground | -- | 3 | -- | -- |
Ignition Voltage - Passenger Seat Back Blower Motor | 1, 4 | 5 | -- | -- |
Ignition Voltage - Passenger Seat Cushion Blower Motor | 1, 4 | 6 | -- | -- |
Passenger Vented Seat Signal | 4 | 4 | 4 | -- |
Passenger Seat Back Blower Motor Ground | -- | 5 | -- | -- |
Passenger Seat Cushion Blower Motor Ground | -- | 6 | -- | -- |
1. Driver Vented Seat is Inoperative 2. Driver Vented Seat Back is Inoperative 3. Driver Vented Seat Cushion is Inoperative 4. Passenger Vented Seat is Inoperative 5. Passenger Vented Seat Back is Inoperative 6. Passenger Vented Seat Cushion is Inoperative | ||||
Circuit/System Description
The driver and passenger vented seats are controlled by separate vented seat switches located in the radio/HVAC control panel. Ignition voltage is supplied to the driver and passenger seat blower motors through the MISC IGN fuse located in the underdood fuse block. Ground for the driver seat blower motors is provided at G200, while ground for the passenger seat blower motors is provided at G201. When a vented seat switch is pressed, a serial data message is sent to the radio. The radio then serves as a gateway to transmit the serial data message to the memory seat module (MSM) indicating the vented seat command. In response to this message, the MSM applies 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. The logic in the blower motors then sets the blower speed to the switch set point. Both blower motors run drawing cabin air around and away from occupant. The MSM then sends a serial data message back to the radio to gateway the information back to the radio/HVAC control panel to either illuminate or turn off the appropriate switch indicator.
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Heated/Vented Seat Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
- Ignition ON, observe the scan tool Radio Driver Cooled Seat Button parameter while pressing the driver VENTED seat switch. The reading should change between Inactive and Active.
- Observe the scan tool Radio Passenger Cooled Seat Button parameter while pressing the passenger VENTED seat switch. The reading should change between Inactive and Active.
- If all scan tool readings test normal and the driver and/or passenger vented seat is inoperative, refer to Circuit/System Testing.
| ⇒ | If not the specified value, replace the radio/HVAC control panel. |
| ⇒ | If not the specified value, replace the radio/HVAC control panel. |
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the appropriate blower motor.
- Ignition OFF, test for less than 5 ohms between the ground circuit terminal B and ground.
- Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal C and ground.
- Connect a test lamp between the signal circuit terminal A and battery voltage.
- Press the VENTED seat switch through the high, medium, and low positions to OFF. The test lamp should illuminate until the OFF position is reached.
- If all circuits test normal, test or replace the blower motor.
| ⇒ | If greater than the specified value, test the ground circuit for an open/high resistance. |
| ⇒ | If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. |
| ⇒ | 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. |
| ⇒ | 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. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for MSM replacement, setup, and programming |
