Pinpoint Test M: The Heated Seats Are Inoperative - Front
Seats
Pinpoint Tests
Pinpoint Test M: The Heated Seats are Inoperative - Front
Refer to Wiring Diagram Set 119, Climate Controlled Seats for schematic and connector information. Diagrams By Number
Normal Operation
The heated seat module is supplied battery voltage on circuit CBX01 (GN/RD), ignition voltage on circuit CBX06 (GY/RD), and ground on circuit GD903 (BK/WH). The HVAC module controls the heated seats by supplying a momentary ground to the heated seat module input circuits when a heated seat button is pressed. If equipped with the navigation and the heated seat buttons are pressed, the Front Controls Interface Module (FCIM) sends a request message to the HVAC module.
The heated seat module monitors the temperature sensor in each seat cushion's heater mat and if the shared return circuit RHS05 (YE/VT) becomes open, the heated seat module will disable both seats.
This pinpoint test is intended to diagnose the following:
- Fuse(s)
- Wiring, terminals or connectors
- Heated seat module
- HVAC module
- FCIM
PINPOINT TEST M: THE HEATED SEATS ARE INOPERATIVE - FRONT
NOTE: The air bag warning indicator illuminates when the correct Restraints Control Module (RCM) fuse is removed and the ignition is ON.
NOTE: The Supplemental Restraint System (SRS) must be fully operational and free of faults before releasing the vehicle to the customer.
-------------------------------------------------
M1 CHECK THE HEATED SEAT OPERATION
- 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 - Driver or The Heated Seat is Inoperative - Passenger. Symptom Related Diagnostic Procedures
No
GO to M2.
-------------------------------------------------
M2 CHECK HEATED SEAT INDICATOR ILLUMINATION
- 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
If equipped with the navigation system, GO to M3.
If not equipped with the navigation system, GO to M4.
-------------------------------------------------
M3 RETRIEVE THE FCIM DTCs
- Enter the following diagnostic mode on the scan tool: Self Test - FCIM.
- Check the FCIM for DTCs.
- 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.
-------------------------------------------------
M4 RETRIEVE THE HVAC MODULE DTCs
- Enter the following diagnostic mode on the scan tool: Self Test - HVAC module.
- Check the HVAC module for DTCs.
- Are any HVAC module DTCs retrieved?
Yes
For all HVAC module DTCs, REFER to the Master DTC Chart in Body Control Systems. Diagnostic Trouble Code (DTC) Chart
No
If equipped with the navigation system, GO to M6.
If not equipped with the navigation system, GO to M5.
-------------------------------------------------
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.
- Does the HVAC system function correctly?
Yes
INSTALL a new HVAC module. TEST the system for normal operation.
No
REFER to Heating and Air Conditioning to diagnose the HVAC concern.
-------------------------------------------------
M6 MONITOR THE FCIM PIDs AND CHECK THE 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 pressing driver and passenger heated seat switch buttons.
- Do the PID values agree with the switch button positions?
Yes
GO to M7.
No
INSTALL a new FCIM. REFER to Accessories and Optional Equipment. TEST the system for normal operation.
-------------------------------------------------
M7 MONITOR THE HVAC MODULE PIDs AND CHECK THE INPUTS
NOTE: The following PIDs are active commands but can be used to check switch 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 switch buttons.
- Monitor HVAC module PIDs while individually pressing driver and passenger heated seat switch 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. TEST the system for normal operation.
No
INSTALL a new HVAC module. TEST the system for normal operation.
-------------------------------------------------
M8 CHECK FOR VOLTAGE TO THE HEATED SEAT MODULE
- Ignition OFF.
- Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering in the General Procedures portion of Restraint Systems.
- Disconnect: Passenger Seat Side Air Bag Module C339.
- 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. Refer to Battery.
- 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) fuse 32 (10A) and Battery Junction Box (BJB) fuse 69 (30A) are OK. If OK, REPAIR the circuit(s). If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short. TEST the system for normal operation. Diagrams By Number
DISCONNECT the battery ground cable.
CONNECT passenger seat side air bag module C339.
REPOWER the SRS. REFER to Restraint Systems.
-------------------------------------------------
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 seat side air bag module C339.
REPOWER the SRS. REFER to Restraint Systems.
-------------------------------------------------
M10 CHECK THE HEATED SEAT MODULE SENSOR RETURN CIRCUIT FOR AN OPEN
- Disconnect: Passenger Seat Cushion Heater C334.
- Measure the resistance between heated seat module C359A-12, circuit RHS05 (YE/VT), harness side and passenger seat cushion heater 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 C339.
REPOWER the SRS. REFER to Restraint Systems.
No
REPAIR the circuit. TEST the system for normal operation.
DISCONNECT the battery ground cable.
CONNECT passenger seat side air bag module C339.
REPOWER the SRS. REFER to Restraint Systems.
-------------------------------------------------