Pinpoint Test N: The Heated Seat Is Inoperative/Does Not Operate Correctly - Driver
Seats
Pinpoint Tests
Pinpoint Test N: The Heated Seat is Inoperative/Does Not Operate Correctly - Driver
Refer to Wiring Diagram Set 119, Climate Controlled Seats for schematic and connector information. Diagrams By Number
Normal Operation
The heated seat module receives ignition voltage on circuit CBP35 (YE/GY), battery voltage on circuit SBB22 (BN/RD) and is supplied ground on circuit GD148 (BK/YE). With the ignition ON and the driver heated seat button pressed, a momentary ground signal is sent from the HVAC module to the heated seat module on circuit CHS29 (WH/BU) to request the system on or off. The heated seat will decrease one setting with each button press (the sequence is high, low, off, high, etc.). The heated seat module supplies voltage to the cushion and backrest heater mats on heater circuit CHS02 (YE/BU). Ground to the heater mats is provided on circuit GD147 (BK/VT). The cushion and backrest heater mats are connected in series and operate together. The heated seat module regulates seat temperature by monitoring resistance of a thermistor type thermostat (part of the cushion heater mat) connected on circuits VHS26 (VT) and RHS05 (YE/VT). The heated seat module is designed to remain on, heating the seat and maintaining temperature until switched off.
The heated seat module monitors the heater output and thermistor circuits for fault detection but does not report DTCs and is not connected to the communication bus circuits. If an open circuit or short to ground occurs, the output is disabled to the heater mats and the heated seat indicators turn off. When a fault is detected, the heated seat module only disables the affected seat. While disabled, the heated seat indicators will flash once with each button press and the heated seat cannot be operated until the system is repaired. The ignition must be cycled OFF to reset the heated seat module from the detected fault.
This pinpoint test is intended to diagnose the following:
- Fuse(s)
- Wiring, terminals or connectors
- Backrest or cushion heater mat
- Heated seat module
- HVAC module
PINPOINT TEST N: THE HEATED SEAT IS INOPERATIVE/DOES NOT OPERATE CORRECTLY - DRIVER
NOTE: The air bag warning indicator illuminates when the correct Restraints Control Module (RCM) fuse is removed and the ignition switch is ON.
NOTE: The Supplemental Restraint System (SRS) must be fully operational and free of faults before releasing the vehicle to the customer.
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N1 CHECK HEATED SEAT CIRCUIT FOR VOLTAGE
- Ignition OFF.
- Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering in the General Procedures of Air Bag Systems.
- Disconnect: Driver Seat Side Air Bag C3226 and Passenger Seat Side Air Bag C3227.
- Disconnect: Driver Safety Belt Buckle Pretensioner C3065 and Passenger Safety Belt Buckle Pretensioner C3066.
- Disconnect: Heated Seat Module C3304.
- WARNING: Make sure no one is in the vehicle and there is nothing blocking or placed in front of any air bag module when the battery is connected. Failure to follow these instructions may result in serious personal injury in the event of an accidental deployment.
- Connect the battery ground cable.
- Measure the voltage between heated seat module C3304-1, circuit SBB22 (BN/RD), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to N2.
No
REPAIR the circuit. TEST the system for normal operation.
DISCONNECT the battery ground cable.
CONNECT driver seat side air bag C3226 and passenger seat side air bag module C3227.
CONNECT driver seat safety belt buckle pretensioner C3065 and passenger seat safety belt buckle pretensioner C3066.
REPOWER the SRS. REFER to Air Bag Systems.
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N2 CHECK THE HEATER MATS RESISTANCE AND HEATER CIRCUITS FOR AN OPEN
- Measure the resistance between heated seat module C3304-9, circuit CHS02 (YE/BU), harness side and ground.
- Is the resistance between 3.2 and 4.4 ohms?
Yes
GO to N10.
No
GO to N3.
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N3 CHECK THE HEATER MATS GROUND CIRCUIT FOR AN OPEN
- Disconnect: Driver Seat Backrest Heater Mat C365.
- Measure the resistance between driver seat backrest heater mat C365-1, circuit GD147 (BK/VT), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
GO to N4.
No
REPAIR the circuit. TEST the system for normal operation.
DISCONNECT the battery ground cable.
CONNECT driver seat side air bag C3226 and passenger seat side air bag module C3227.
CONNECT driver seat safety belt buckle pretensioner C3065 and passenger seat safety belt buckle pretensioner C3066.
REPOWER the SRS. REFER to Air Bag Systems.
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N4 CHECK THE HEATED SEAT FEED CIRCUIT FOR AN OPEN AND A SHORT TO GROUND
- Disconnect: Driver Seat Cushion Heater Mat C364.
- Measure the resistance between:
- heated seat module C3304-9, circuit CHS02 (YE/BU), harness side and driver seat cushion heater mat C364-1, circuit CHS02 (YE/BU), harness side.
- heated seat module C3304-9, circuit CHS02 (YE/BU), harness side and ground.
- Is the resistance less than 5 ohms between C3304-9 and C364-1 and greater than 10,000 ohms between C3304-9 and ground?
Yes
GO to N5.
No
REPAIR the circuit. TEST the system for normal operation.
DISCONNECT the battery ground cable.
CONNECT driver seat side air bag C3226 and passenger seat side air bag module C3227.
CONNECT driver seat safety belt buckle pretensioner C3065 and passenger seat safety belt buckle pretensioner C3066.
REPOWER the SRS. REFER to Air Bag Systems.
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N5 CHECK THE SEAT CUSHION HEATER MAT FOR AN OPEN
NOTE: Heater mat resistance tolerances are tight. Resistance can vary with temperature. Measurements should be carried out with the seat at room temperature.
- Measure the resistance between seat cushion heater mat C364 pins 1 and 4, component side.
- Is the resistance between 1.8 and 2.4 ohms?
Yes
GO to N6.
No
INSTALL a new cushion heater mat. REFER to Seat Cushion Cover - Front Seat Cushion Cover - Front. TEST the system for normal operation.
DISCONNECT the battery ground cable. CONNECT driver seat side air bag module C327. CONNECT passenger seat side air bag module C313.
REPOWER the SRS. REFER to Air Bag Systems.
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N6 CHECK THE SEAT CUSHION HEATER MAT FOR AN INTERMITTENT OPEN
- Carry out the following measurements with an occupant in the seat and check for an open heater mat with weight on the seat.
- Measure the resistance between seat cushion heater mat C364 pins 1 and 4, component side.
- Is the backrest heater mat resistance between 1.8 and 2.4 ohms with seat occupied?
Yes
GO to N7.
No
INSTALL a new seat cushion heater mat. REFER to Seat Cushion Cover - Front Seat Cushion Cover - Front. TEST the system for normal operation.
DISCONNECT the battery ground cable.
CONNECT driver seat side air bag C3226 and passenger seat side air bag module C3227.
CONNECT driver seat safety belt buckle pretensioner C3065 and passenger seat safety belt buckle pretensioner C3066.
REPOWER the SRS. REFER to Air Bag Systems.
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N7 CHECK THE HEATER MAT CIRCUIT FOR AN OPEN AND A SHORT TO GROUND
- Measure the resistance between:
- driver seat cushion heater mat C364-4, circuit CHS11 (VT/GN), harness side and driver seat backrest heater mat C365-2, circuit CHS11 (VT/GN), harness side.
- driver seat cushion heater mat C364-4, circuit CHS11 (VT/GN), harness side and ground.
- Is resistance less than 5 ohms between C364-4 and C365-2, and greater than 10,000 ohms between C364-4 and ground?
Yes
GO to N8.
No
REPAIR the circuit. TEST the system for normal operation.
DISCONNECT the battery ground cable.
CONNECT driver seat side air bag C3226 and passenger seat side air bag module C3227.
CONNECT driver seat safety belt buckle pretensioner C3065 and passenger seat safety belt buckle pretensioner C3066.
REPOWER the SRS. REFER to Air Bag Systems.
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N8 CHECK THE BACKREST HEATER MAT FOR AN OPEN
- Measure the resistance between driver seat backrest heater mat C365 pins 1 and 2, component side.
- Is the resistance between 1.4 and 2.0 ohms?
Yes
GO to N9.
No
INSTALL a new backrest heater mat. REFER to Seat Cushion Cover - Front Seat Cushion Cover - Front. TEST the system for normal operation.
DISCONNECT the battery ground cable.
CONNECT driver seat side air bag C3226 and passenger seat side air bag module C3227.
CONNECT driver seat safety belt buckle pretensioner C3065 and passenger seat safety belt buckle pretensioner C3066.
REPOWER the SRS. REFER to Air Bag Systems.
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N9 CHECK THE BACKREST HEATER MAT FOR AN INTERMITTENT OPEN
- Carry out the following measurements with an occupant in the seat and check for an open heater mat with weight on the seat.
- Measure the resistance between seat backrest heater mat C365 pins 1 and 2, component side.
- Is the resistance between 1.4 and 2.0 ohms with seat occupied?
Yes
GO to N14.
No
INSTALL a new backrest heater mat. TEST the system for normal operation.
DISCONNECT the battery ground cable.
CONNECT driver seat side air bag C3226 and passenger seat side air bag module C3227.
CONNECT driver seat safety belt buckle pretensioner C3065 and passenger seat safety belt buckle pretensioner C3066.
REPOWER the SRS. REFER to Air Bag Systems.
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N10 CHECK THE TEMPERATURE SENSOR CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition ON.
- Measure the voltage between heated seat module C3304a-10, circuit VHS26 (VT), harness side and ground.
- Is any voltage present?
Yes
REPAIR the circuit. GO to N14 to check the temperature sensor for damage. If temperature sensor is OK, TEST the system for normal operation. If not OK, INSTALL a new seat cushion heater mat.
DISCONNECT the battery ground cable.
CONNECT driver seat side air bag C3226 and passenger seat side air bag module C3227.
CONNECT driver seat safety belt buckle pretensioner C3065 and passenger seat safety belt buckle pretensioner C3066.
REPOWER the SRS. REFER to Air Bag Systems.
No
GO to N11.
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N11 CHECK THE TEMPERATURE SENSOR CIRCUITS FOR AN OPEN AND A SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between:
- heated seat module C3304-10, circuit VHS26 (VT), harness side and C3304-13, circuit RHS05 (YE/VT), harness side.
- heated seat module C3304-13, circuit RHS05 (YE/VT), harness side and ground.
- Is the resistance greater than 300 and less than 300,000 ohms between C3304-10 and C3304-13 and greater than 10,000 ohms between C3304-13 and ground?
Yes
GO to N14.
No
GO to N12.
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N12 CHECK THE TEMPERATURE SENSOR CIRCUIT FOR AN OPEN AND A SHORT TO GROUND
- Disconnect: Driver Seat Cushion Heater Mat C364.
- Measure the resistance between:
- heated seat module C3304-10, circuit VHS26 (VT), harness side and seat cushion heater mat C364-2, circuit VHS26 (VT), harness side.
- heated seat module C3304-10, circuit VHS26 (VT), harness side and ground.
- Is the resistance less than 5 ohms between C3304-10 and C364-2, and greater than 10,000 ohms between C3304-10 and ground?
Yes
GO to N13.
No
REPAIR the circuit. TEST the system for normal operation.
DISCONNECT the battery ground cable.
CONNECT driver seat side air bag C3226 and passenger seat side air bag module C3227.
CONNECT driver seat safety belt buckle pretensioner C3065 and passenger seat safety belt buckle pretensioner C3066.
REPOWER the SRS. REFER to Air Bag Systems.
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N13 CHECK THE TEMPERATURE SENSOR GROUND CIRCUIT FOR AN OPEN
- Measure the resistance between heated seat module C3304-13, circuit RHS05 (YE/VT), harness side and driver seat cushion heated seat element C364-3, circuit RHS05 (YE/VT), harness side.
- Is the resistance less than 5 ohms between C3304-13 and C364-3?
Yes
INSTALL a new cushion heater mat. REFER to Seat Cushion Cover - Front Seat Cushion Cover - Front. TEST the system for normal operation.
DISCONNECT the battery ground cable. CONNECT driver seat side air bag module C327. CONNECT passenger seat side air bag module C313.
REPOWER the SRS. REFER to Air Bag Systems.
No
REPAIR the circuit. TEST the system for normal operation.
DISCONNECT the battery ground cable.
CONNECT driver seat side air bag C3226 and passenger seat side air bag module C3227.
CONNECT driver seat safety belt buckle pretensioner C3065 and passenger seat safety belt buckle pretensioner C3066.
REPOWER the SRS. REFER to Air Bag Systems.
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N14 CHECK THE HEATED SEAT SWITCH CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: HVAC Module C228b.
- Ignition ON.
- Measure the voltage between heated seat module C3304-12, circuit CHS29 (WH/BU), harness side and ground.
- Is any voltage present?
Yes
REPAIR the circuit. TEST the system for normal operation.
DISCONNECT the battery ground cable.
CONNECT driver seat side air bag C3226 and passenger seat side air bag module C3227.
CONNECT driver seat safety belt buckle pretensioner C3065 and passenger seat safety belt buckle pretensioner C3066.
REPOWER the SRS. REFER to Air Bag Systems.
No
GO to N15.
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N15 CHECK THE HEATED SEAT SWITCH CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between heated seat module C3304-12, circuit CHS29 (WH/BU), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to N16.
No
REPAIR the circuit. TEST the system for normal operation.
DISCONNECT the battery ground cable.
CONNECT driver seat side air bag C3226 and passenger seat side air bag module C3227.
CONNECT driver seat safety belt buckle pretensioner C3065 and passenger seat safety belt buckle pretensioner C3066.
REPOWER the SRS. REFER to Air Bag Systems.
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N16 CHECK THE HEATED SEAT SWITCH CIRCUIT FOR AN OPEN
- Measure the resistance between heated seat module C3304-12, circuit CHS29 (WH/BU), harness side and HVAC module C228b-6, circuit CHS29 (WH/BU), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to N17.
No
REPAIR the circuit. TEST the system for normal operation.
DISCONNECT the battery ground cable.
CONNECT driver seat side air bag C3226 and passenger seat side air bag module C3227.
CONNECT driver seat safety belt buckle pretensioner C3065 and passenger seat safety belt buckle pretensioner C3066.
REPOWER the SRS. REFER to Air Bag Systems.
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N17 CHECK THE HVAC MODULE OUTPUT
- Connect: HVAC Module C228b.
- Connect: Heated Seat Module C3304.
- Ignition ON.
- NOTE: The following measurement must be taken by back-probing the heated seat module C3304.
- NOTE: The voltage on circuit CHS29 (WH/BU) should drop momentarily when the driver heated seat control button is pressed.
- Measure the voltage between heated seat module circuit CHS29 (WH/BU), harness side and ground by back-probing heated seat module C3304-12 to ground. Press the heated seat button and note the voltage.
- Is the voltage greater than 10 volts before pressing the button, then momentarily drops when the button is pressed?
Yes
INSTALL a new heated seat module. REFER to Heated Seat Module - Front Heated Seat Module - Front. TEST the system for normal operation.
DISCONNECT the battery ground cable.
CONNECT driver seat side air bag C3226 and passenger seat side air bag module C3227.
CONNECT driver seat safety belt buckle pretensioner C3065 and passenger seat safety belt buckle pretensioner C3066.
REPOWER the SRS. REFER to Air Bag Systems.
No
If the voltage is greater than 10 volts but did not drop when the driver heated seat button was pressed, INSTALL a new HVAC module.
If the voltage is less than 10 volts, INSTALL a new heated seat module. REFER to Heated Seat Module - Front Heated Seat Module - Front.
TEST the system for normal operation.
DISCONNECT the battery ground cable.
CONNECT driver seat side air bag C3226 and passenger seat side air bag module C3227.
CONNECT driver seat safety belt buckle pretensioner C3065 and passenger seat safety belt buckle pretensioner C3066.
REPOWER the SRS. REFER to Air Bag Systems.
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