Pinpoint Test M: The Heated Seats Are Inoperative - Driver And Front Passenger
Seats
Pinpoint Tests
Pinpoint Test M: The Heated Seats are Inoperative - Driver and Front Passenger
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 CBX06 (GY/RD), battery voltage on circuit CBX01 (GN/RD) and ground on circuit GD903 (BK/WH). When ignition voltage is supplied and a heated seat button on the Front Controls Interface Module (FCIM) is pressed, the Medium Speed Controller Area Network (MS-CAN) communicates the command to the HVAC module. The HVAC module then sends a momentary ground to the driver command circuit (CHS29 WH/BU) or passenger command circuit (CHS30 GY/YE) to turn the heated seat on. Upon receiving a command, the heated seat module will decrease one setting (the sequence is high, low, off, high, etc.). The heated seat module monitors temperature sensors contained within the cushion heater mats on the driver and front passenger seats. The temperature sensors share return circuit RHS05 (YE/VT) to the heated seat module. If the temperature sensor return circuit opens (resistance greater than 300,000 ohms), the heated seat module will disable the outputs to both seats. The system will remain disabled until the circuit is repaired and the heated seat module is reset by cycling the ignition OFF and ON.
This pinpoint test is intended to diagnose the following:
- Fuse(s)
- Wiring, terminals or connectors
- FCIM
- HVAC module
- Heated seat module
PINPOINT TEST M: THE HEATED SEATS ARE INOPERATIVE - DRIVER AND FRONT PASSENGER
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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M1 CHECK HEATED SEAT OPERATION
- Ignition OFF.
- Start the engine.
- Verify both heated seats do not heat.
- Does either heated seat operate?
Yes
GO to Symptom Chart to diagnose the heated seat is inoperative/does not operate correctly - driver or the heated seat is inoperative/does not operate correctly - passenger. Symptom Related Diagnostic Procedures
No
GO to M2.
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M2 CHECK HEATED SEAT INDICATOR ILLUMINATION
- Ignition OFF.
- Ignition ON.
- Verify system indicator illumination.
- When pressing and releasing each heated seat button individually, does any heated seat indicator illuminate or flash and then turn off?
Yes
GO to M8.
No
GO to M3.
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M3 CHECK THE FCIM FOR DTCs
- Enter the following diagnostic mode on the scan tool: Self Test - FCIM.
- Are any FCIM DTCs retrieved?
Yes
For all FCIM DTCs, REFER to the Master DTC Chart in Body Control Systems. Diagnostic Trouble Code (DTC) Chart
No
GO to M4.
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M4 CHECK THE HVAC MODULE FOR DTCs
- Enter the following diagnostic mode on the scan tool: Self Test - HVAC Module.
- Are any HVAC module DTCs retrieved?
Yes
For any HVAC module DTCs, REFER to the Master DTC Chart in Body Control Systems. Diagnostic Trouble Code (DTC) Chart
No
For vehicles without navigation, GO to M5.
For vehicles with navigation, GO to M6.
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M5 CHECK THE HVAC FUNCTIONS
NOTE: The purpose of this step is to verify the HVAC module is able to receive and process inbound command messages from the communication bus and demonstrate the HVAC module is operational. This indicates the FCIM buttons may not be sending the commands correctly.
- Operate the HVAC system using the buttons on the FCIM and check for correct HVAC function.
- Does the HVAC system function correctly?
Yes
INSTALL a new FCIM. TEST the system for normal operation.
No
REFER to Heating and Air Conditioning to diagnose the HVAC concern.
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M6 MONITOR THE FCIM PIDs AND CHECK INPUTS
- Enter the following diagnostic mode on the scan tool: DataLogger - FCIM - PIDs.
- Driver Heated Seat (CC_SW_D_HSEATS)
- Passenger Heated Seat (CC_SW_P_HSEATS)
- Monitor the FCIM PIDs while individually pushing the driver and passenger heated seat buttons.
- Do the PID values agree with the switch button positions?
Yes
GO to M7.
No
INSTALL a new FCIM. TEST the system for normal operation.
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M7 MONITOR THE HVAC MODULE PIDs AND CHECK INPUTS
- Enter the following diagnostic mode on the scan tool: DataLogger - HVAC Module - PIDs.
- Left Seat Heater (ST_HEAT_LT)
- Right Seat Heater (ST_HEAT_RT)
- NOTE: The PID data will quickly flicker on and off. Watch closely when pressing the FCIM buttons.
- Monitor HVAC module PIDs while individually pushing the driver and passenger heated seat buttons.
- Do the PID values agree with the switch button positions?
Yes
The fault is intermittent, CHECK for causes of the intermittent fault. INSPECT the connectors, terminals and wiring. ATTEMPT to recreate the fault by flexing the wire harness and operating the system. CHECK the electrical connectors for corrosion, poor pin contact or pushed-out pins. REPAIR any intermittent concerns found and TIGHTEN any loose HVAC module connector pins. REPEAT the self-test. CLEAR the DTCs. CHECK the system for normal operation.
No
INSTALL a new HVAC module. TEST the system for normal operation.
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M8 CHECK THE VOLTAGE TO THE HEATED SEAT MODULE
- Ignition OFF.
- Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering in the General Procedures of Air Bag Systems.
- Disconnect: Passenger Seat Side Air Bag Module C3137.
- Disconnect: Passenger Safety Belt Buckle Pretensioner C3066.
- Disconnect: Heated Seat Module C359b.
- 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.
- Ignition ON.
- Measure the voltage between:
- heated seat module C359b-1, circuit CBX01 (GN/RD), harness side and ground.
- heated seat module C359b-2, circuit SBX06 (GY/RD), harness side and ground.
- Are the voltages greater than 10 volts?
Yes
GO to M9.
No
VERIFY Smart Junction Box (SJB) fuses 18(20A) and 35 (10A) are OK. If OK, REPAIR the affected circuit. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short. TEST the system for normal operation.
DISCONNECT the battery ground cable.
CONNECT passenger safety belt buckle pretensioner C3066.
CONNECT passenger seat side air bag module C3137.
REPOWER the SRS. REFER to Air Bag Systems.
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M9 CHECK THE HEATED SEAT MODULE GROUND CIRCUIT FOR AN OPEN
- Ignition OFF.
- Measure the resistance between heated seat module C359b-5, circuit GD903 (BK/WH), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
GO to M10.
No
REPAIR the circuit. TEST the system for normal operation.
DISCONNECT the battery ground cable.
CONNECT passenger safety belt buckle pretensioner C3066.
CONNECT passenger seat side air bag module C3137.
REPOWER the SRS. REFER to Air Bag Systems.
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M10 CHECK HEATED SEAT MODULE SENSOR RETURN CIRCUIT FOR AN OPEN
- Disconnect: Heated Seat Module C359a.
- Disconnect: Passenger Seat Cushion Heater Mat C334.
- Measure the resistance between heated seat module C359a-12, circuit RHS05 (YE/VT), harness side and passenger seat cushion heater mat C334-3, circuit RHS05 (YE/VT), harness side.
- Is the resistance less than 5 ohms?
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 passenger seat side air bag module C3137.
CONNECT passenger seat safety belt buckle pretensioner C3066.
REPOWER the SRS. REFER to Air Bag Systems.
No
REPAIR the circuit. TEST the system for normal operation.
DISCONNECT the battery ground cable.
CONNECT passenger safety belt buckle pretensioner C3066.
CONNECT passenger seat side air bag module C3137.
REPOWER the SRS. REFER to Air Bag Systems.
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