Part 2
Seats
Pinpoint Test AS: DTC B272B
Refer to Wiring Diagram Set 119, Climate Controlled Seats for schematic and connector information Electrical Diagrams.
Normal Operation
Both the driver and front passenger climate controlled seats are independently controlled electronically by the Dual Climate Controlled Seat Module (DCSM) mounted to the bottom of the passenger seat cushion. The climate controlled seat system only operates with the engine running, however, if using a scan tool to command the DCSM (Dual Climate Controlled Seat Module), diagnostic testing can be carried out with the ignition ON engine OFF. The system receives voltage from Battery Junction Box (BJB) fuse 67 (40A) feeding battery voltage on circuit SBB08 (VT/RD) into DCSM (Dual Climate Controlled Seat Module) C3265A pins E and F. If voltage is disconnected from either pin E or F of DCSM (Dual Climate Controlled Seat Module) C3265A with the voltage connection remaining on the other circuit, both seats will remain operational because the voltage feed circuits are connected internally in the DCSM (Dual Climate Controlled Seat Module). However, if a fault occurs setting a DTC specific to either climate controlled seat, only the affected seat will be disabled by the module and the other will remain operational.
Each driver and front passenger seat cushion is equipped with a Thermo-Electric Device (TED) assembly that includes a seat blower (fan motor, serviced as an assembly with the TED (Thermo-Electric Device)). Similarly, each driver and front passenger seat backrest is also equipped with its own TED (Thermo-Electric Device) assembly with blower. Cabin air is drawn through the blower and distributed to each of the TED (Thermo-Electric Device) modules located in the seat cushion and backrest. The TEDs (Thermo-Electric Devices) then heat or cool the air. The air is then directed into the foam pad and manifold where it is distributed along the surface of the cushion and backrest of the seat. Once the system is activated, the DCSM (Dual Climate Controlled Seat Module) uses a set of flexible algorithms to control the heating/cooling modes and the blower speed, dependant on the climate controlled seat switch settings.
- DTC B272B (Passenger Back-Over Temp Detected)- In the heating mode, if the passenger seat backrest TED (Thermo-Electric Device) temperature exceeds 85°C (185°F) for more than 4 seconds, the TED (Thermo-Electric Device) is disconnected or the duct is blocked, the DCSM (Dual Climate Controlled Seat Module) shuts down the passenger seat system and set this DTC. Incorrect use of the climate controlled seat by repeated switching between heat and cool modes or excessive passenger compartment temperature also sets this DTC.
- DTC B272B (Passenger Back-Over Temp Detected)- In the cooling mode, if the passenger seat backrest TED (Thermo-Electric Device) temperature exceeds 70°C (158°F) for more than 4 seconds, the TED (Thermo-Electric Device) is disconnected or the duct is blocked, the DCSM (Dual Climate Controlled Seat Module) shuts down the passenger seat system and set this DTC. Incorrect use of the climate controlled seat by repeated switching between heat and cool modes or excessive passenger compartment temperature also sets this DTC.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Restricted passenger seat backrest TED (Thermo-Electric Device) filter
- Crushed or restricted passenger seat backrest foam pad
- Crushed or restricted passenger seat backrest climate controlled seat manifold
- Passenger seat backrest TED (Thermo-Electric Device) assembly
- DCSM (Dual Climate Controlled Seat Module)
AS10 CHECK THE PASSENGER SEAT BACKREST BLOWER CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition ON.
- Measure the voltage between DCSM (Dual Climate Controlled Seat Module) C3265C-7, circuit CHS08 (BN/YE), harness side and ground.
Is any voltage present?
Yes
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C3052.
CONNECT passenger seat safety belt buckle pretensioner C3050.
REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
No
GO to AS11.
AS11 CHECK THE PASSENGER SEAT BACKREST BLOWER CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between DCSM (Dual Climate Controlled Seat Module) C3265C-8, circuit CHS14 (GN), harness side and ground.
Is the resistance greater than 10,000 ohms?
Yes
GO to AS12.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C3052.
CONNECT passenger seat safety belt buckle pretensioner C3050.
REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
AS12 CHECK THE PASSENGER SEAT BACKREST BLOWER CIRCUITS FOR AN OPEN
- Measure the resistance between:
- DCSM (Dual Climate Controlled Seat Module) C3265C-8, circuit CHS14 (GN), harness side and passenger seat backrest TED (Thermo-Electric Device) C3039-2, circuit CHS13 (VT/BN) (10-way power seat) or C3316-2, circuit CHS14 (GN) (6-way power seat), harness side.
- DCSM (Dual Climate Controlled Seat Module) C3265C-7, circuit CHS08 (BN/YE), harness side and passenger seat backrest TED (Thermo-Electric Device) C3039-4, circuit CHS03 (GN/BN) (10-way power seat) or C3316-4, circuit CHS08 (BN/YE) (6-way power seat), harness side.
Are the resistances less than 5 ohms?
Yes
GO to AS13.
No
REPAIR the circuit(s). CLEAR the DTCs. REPEAT the self-test.
DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C3052.
CONNECT passenger seat safety belt buckle pretensioner C3050.
REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
AS13 CHECK THE PASSENGER SEAT BACKREST BLOWER RESISTANCE
- NOTICE: The ohmmeter must be connected with the positive lead to pin 2 and the negative lead to pin 4 when measuring. Ohmmeter leads incorrectly connected results in false readings and leads to incorrect identification of components that are not damaged.
Measure the resistance between passenger seat backrest TED (Thermo-Electric Device) C3039 (10-way power seat) or C3316 (6-way power seat) pin 2 and pin 4, component side.
Is the resistance between 4,000 ohms and 10,000 ohms?
Yes
GO to AS14.
No
INSTALL a new passenger seat backrest TED (Thermo-Electric Device). REFER to Seat Backrest Thermo-Electric Device . CLEAR the DTCs. REPEAT the self-test.
CONNECT passenger seat safety belt buckle pretensioner C3050.
DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C3052.
REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
AS14 CHECK THE PASSENGER SEAT BACKREST BLOWER SPEED CONTROL RESISTANCE
- NOTICE: The ohmmeter must be connected with the positive lead to pin 7 and the negative lead to pin 4 when measuring. Ohmmeter leads incorrectly connected results in false readings and leads to incorrect identification of components that are not damaged.
Measure the resistance between passenger seat backrest TED (Thermo-Electric Device) C3039 (10-way power seat) or C3316 (6-way power seat) pin 7 and pin 4, component side.
Is the resistance between 240K ohms and 400K ohms?
Yes
GO to AS15.
No
INSTALL a new passenger seat backrest TED (Thermo-Electric Device). REFER to Seat Backrest Thermo-Electric Device . CLEAR the DTCs. REPEAT the self-test.
DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C3052.
CONNECT passenger seat safety belt buckle pretensioner C3050.
REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
AS15 CHECK THE PASSENGER SEAT BACKREST TED (Thermo-Electric Device) INSTALLATION AND FOR CRUSHED SEAT BACKREST
- Ignition OFF.
- Remove the passenger seat backrest cover. Refer to Seat Backrest Cover- Front .
- Inspect the passenger seat backrest for the following:
- Is the passenger seat backrest TED (Thermo-Electric Device) correctly installed?
- Is the passenger seat backrest foam pad crushed or restricted?
- Is the passenger seat backrest climate controlled seat manifold crushed or restricted?
Is the passenger seat backrest TED (Thermo-Electric Device) correctly installed and are there no signs of damage to the foam pad and manifold?
Yes
INSTALL the passenger seat backrest cover and seat and GO to AS18.
No
CORRECTLY install the passenger seat backrest TED (Thermo-Electric Device) or INSTALL a new passenger seat backrest foam pad and/or climate controlled seat manifold. CONNECT the battery ground cable. CLEAR the DTCs. REPEAT the self-test.
DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C3052.
CONNECT passenger seat safety belt buckle pretensioner C3050.
REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
AS16 CHECK THE PASSENGER SEAT BACKREST TED (Thermo-Electric Device) THERMISTOR AND WIRING
- Ignition OFF.
- Depower the SRS (Supplemental Restraint System). Refer to Supplemental Restraint System (SRS) Depowering and Repowering in the General Procedures portion of Restraints and Safety Systems &/or Air Bag Systems.
- Disconnect: Passenger Seat Side Air Bag C3052.
- Disconnect: Passenger Seat Safety Belt Buckle Pretensioner C3050.
- Disconnect: DCSM (Dual Climate Controlled Seat Module) C3265B.
- 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 resistance between DCSM (Dual Climate Controlled Seat Module) C3265B-4, circuit VHS36 (YE/BU), harness side and C3305B-5 circuit RHS20 (GN/BU), harness side. Note the ambient temperature and refer to the following table.
Temperature Resistance 0-10°C (32-50°F) 2,782-1,663 ohms 10-20°C (50-68°F) 1,837-1,140 ohms 20-30°C (68-86°F) 1,260-806 ohms 30-40°C (86-104°F) 893-570 ohms 40-50°C (104-122°F) 630-428 ohms
Is the resistance within the limits indicated?
Yes
GO to AS18.
No
GO to AS17.
AS17 CHECK THE PASSENGER SEAT BACKREST TED (Thermo-Electric Device) THERMISTOR
- Measure the resistance between passenger seat backrest TED (Thermo-Electric Device) C3039 (10-way power seat) or C3316 (6-way power seat) pin 5 and pin 8, component side. Note the ambient temperature and refer to the following table.
Temperature Resistance 0-10°C (32-50°F) 2,782-1,663 ohms 10-20°C (50-68°F) 1,837-1,140 ohms 20-30°C (68-86°F) 1,260-806 ohms 30-40°C (86-104°F) 893-570 ohms 40-50°C (104-122°F) 630-428 ohms
Is the resistance within the limits indicated?
Yes
REPAIR circuit VHS35 (VT/OG)/VHS36 (YE/BU) or RHS15 (GY/BN)/RHS20 (GN/BU) for an open or high resistance. CLEAR the DTCs. REPEAT the self-test.
DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C3052.
CONNECT passenger seat safety belt buckle pretensioner C3050.
REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
No
INSTALL a new TED (Thermo-Electric Device). REFER to Seat Backrest Thermo-Electric Device . CLEAR the DTCs. REPEAT the self-test.
DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C3052.
CONNECT passenger seat safety belt buckle pretensioner C3050.
REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
AS18 CHECK THE PASSENGER SEAT BACKREST TED (Thermo-Electric Device) HEATING/COOLING CIRCUITRY CURRENT DRAW
- Connect: All DCSM (Dual Climate Controlled Seat Module), TED (Thermo-Electric Device) and Body Harness-to-Seat Harness Connectors.
- NOTICE: It may be necessary to open the seat wire harness conduit to allow placing the inductive current probe around the circuit as described in the following step. Care must be taken when opening up the wire harness so as not to damage any wiring or connectors. Do not damage any wiring or induce stress on any wiring or connectors. Close up the wire harness once repairs to the seat are complete.
NOTE: Use a commercially available inductive current probe (such as Electronic Specialties Current Probe/Multimeter 685 or a Fluke I410 [used with a digital multimeter]) or the low current probe from the Vehicle Measurement Module available for use with Integrated Diagnostic System (IDS). If these are unavailable, the inductive current probe feature from a battery tester may be substituted.
Place an inductive current probe around circuit CHS06 (BU/BN) near DCSM (Dual Climate Controlled Seat Module) C3305A-C and monitor the current draw.
- Start the vehicle and set the passenger seat to HIGH heat.
Is the current draw less than 11 amps?
Yes
GO to AS19.
No
INSTALL a new passenger seat backrest TED (Thermo-Electric Device). REFER to Seat Backrest Thermo-Electric Device . CLEAR the DTCs. REPEAT the self-test.
DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C3052.
CONNECT passenger seat safety belt buckle pretensioner C3050.
REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
AS19 CHECK RESISTANCE OF THE PASSENGER SEAT BACKREST TED (Thermo-Electric Device) AND WIRING
- Ignition OFF.
- Disconnect: DCSM (Dual Climate Controlled Seat Module) C3265A.
- Measure the resistance between DCSM (Dual Climate Controlled Seat Module) C3265A-C circuit CHS06 (BU/BN), harness side and C3265A-D, circuit RHS06 (WH), harness side.
Is the resistance between 0.9 and 10 ohms?
Yes
GO to AS21.
No
GO to AS20.
AS20 CHECK THE RESISTANCE OF THE PASSENGER SEAT BACKREST TED (Thermo-Electric Device)
- Disconnect: Passenger Seat Backrest TED (Thermo-Electric Device) C3039 (with 10-way power seat) or C3316 (with 6-way power seat).
- Measure the resistance between passenger seat backrest TED (Thermo-Electric Device) C3039 (10-way power seat) or C3316 (6-way power seat) pin 1 and pin 3, component side.
Is the resistance between 0.9 and 10 ohms?
Yes
REPAIR circuit CHS01 (GY/VT)/CHS06 (BU/BN) or RHS01 (WH/VT)/RHS06 (WH) for an open or high resistance. CLEAR the DTCs. REPEAT the self-test.
DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C3052.
CONNECT passenger seat safety belt buckle pretensioner C3050.
REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
No
INSTALL a new passenger seat backrest TED (Thermo-Electric Device). REFER to Seat Backrest Thermo-Electric Device . CLEAR the DTCs. REPEAT the self-test.
DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C3052.
CONNECT passenger seat safety belt buckle pretensioner C3050.
REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
AS21 CHECK FOR CORRECT DCSM (Dual Climate Controlled Seat Module) OPERATION
- Inspect the DCSM (Dual Climate Controlled Seat Module) and passenger seat backrest TED (Thermo-Electric Device) harness and component side connectors and the body harness-to-seat harness connectors for:
- corrosion
- damaged pins
- pushed-out pins
- Connect: All DCSM (Dual Climate Controlled Seat Module), TED (Thermo-Electric Device) and Body Harness-to-Seat Harness Connectors.
- Make sure the connectors are seated correctly.
- Start the engine.
- Set the passenger seat to OFF.
- Enter the following diagnostic mode on the scan tool: Clear DTCs - DCSM (Dual Climate Controlled Seat Module).
- Attempt to recreate the fault. With the engine still running set the passenger seat to HIGH heat for at least 15 minutes.
Is the concern still present?
Yes
INSTALL a new DCSM (Dual Climate Controlled Seat Module). REFER to Dual Climate Controlled Seat Module (DCSM) . REPEAT the self-test. TEST the system for normal operation.
DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C3052.
CONNECT passenger seat safety belt buckle pretensioner C3050.
REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.
DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C3052.
CONNECT passenger seat safety belt buckle pretensioner C3050.
REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.