Part 2

Seats

Pinpoint Test AT: DTC B272C

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.

A differential fault occurs when the cushion and backrest TEDs (Thermo-Electric Devices) on the seat are reporting temperatures to the DCSM (Dual Climate Controlled Seat Module) with a difference between them of 60°C (108°F) or greater. This can result from an airflow restriction or a circuit fault at either TED (Thermo-Electric Device). If a TED (Thermo-Electric Device) and manifold is clear of obstruction and is operational, the other TED (Thermo-Electric Device) and circuitry on the seat should be checked. It is important to note that a TED (Thermo-Electric Device) with a higher temperature may be operating correctly and not the area of concern. The other TED (Thermo-Electric Device) may be indicating a much lower temperature, causing the DTC to set.

- DTC B272C (Driver Differential Temperature Fault)- If there is a temperature differential between the driver backrest and cushion TED (Thermo-Electric Device) of 60°C (108°F) or more for more than 4 seconds, the TED (Thermo-Electric Device) is disconnected or the duct is blocked, this DTC will set. When this happens the first time in a key cycle, the DCSM (Dual Climate Controlled Seat Module) puts the driver seat system into recovery mode, refer to Principles of Operation. Principles Of Operation If the system is able to recover, it will function normally. If the system is able to recover and it occurs a second time in the same key cycle, the DCSM (Dual Climate Controlled Seat Module) will shut down the driver seat system.

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors

- Restricted cushion or backrest TED (Thermo-Electric Device) filter

- Crushed or restricted cushion or backrest foam pad

- Crushed or restricted cushion or backrest climate controlled seat manifold

- Cushion or backrest TED (Thermo-Electric Device) assembly

- DCSM (Dual Climate Controlled Seat Module)

AT16 CHECK THE THERMISTOR CIRCUIT FOR A SHORT TO VOLTAGE

- 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: Driver Seat Safety Belt Buckle Pretensioner C3049 and Passenger Seat Safety Belt Buckle Pretensioner C3050.

- Disconnect: Driver Seat Side Air Bag C3051 and Passenger Seat Side Air Bag C3052.

- 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.

- Ignition ON.

- Measure the voltage between DCSM (Dual Climate Controlled Seat Module) C3265B-7, circuit VHS26 (VT), harness side and ground.

Is the voltage less than 0.5 volt?

Yes
GO to AT17.

No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.

DISCONNECT the battery ground cable. CONNECT driver seat safety belt buckle pretensioner C3049 and passenger seat safety belt buckle pretensioner C3050.

CONNECT driver seat side air bag module C3051 and passenger seat side air bag module C3052.

REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.

AT17 CHECK THE THERMISTOR CIRCUIT FOR A SHORT TO GROUND

- Ignition OFF.

- Measure the resistance between DCSM (Dual Climate Controlled Seat Module) C3265B-7, circuit VHS26 (VT), harness side and ground.

Is the resistance greater than 10,000 ohms?

Yes
GO to AT18.

No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.

DISCONNECT the battery ground cable. CONNECT driver seat safety belt buckle pretensioner C3049 and passenger seat safety belt buckle pretensioner C3050.

CONNECT driver seat side air bag module C3051 and passenger seat side air bag module C3052.

REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.

AT18 CHECK THE THERMISTOR AND WIRING

- Measure the resistance between DCSM (Dual Climate Controlled Seat Module) C3265B-7, circuit VHS26 (VT), harness side and DCSM (Dual Climate Controlled Seat Module) C3265B-8, circuit RHS05 (YE/VT), 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
INSTALL a new DCSM (Dual Climate Controlled Seat Module). REFER to Dual Climate Controlled Seat Module (DCSM) . CLEAR the DTCs. REPEAT the self-test.

DISCONNECT the battery ground cable. CONNECT driver seat safety belt buckle pretensioner C3049 and passenger seat safety belt buckle pretensioner C3050.

CONNECT driver seat side air bag module C3051 and passenger seat side air bag module C3052.

REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.

No
GO to AT19.

AT19 CHECK THE THERMISTOR

- Disconnect: Cushion TED (Thermo-Electric Device) C3035.

- Measure the resistance between cushion TED (Thermo-Electric Device) 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 the affected circuit(s). CLEAR the DTCs. REPEAT the self-test.

DISCONNECT the battery ground cable. CONNECT driver seat safety belt buckle pretensioner C3049 and passenger seat safety belt buckle pretensioner C3050.

CONNECT driver seat side air bag module C3051 and passenger seat side air bag module C3052.

REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.

No
INSTALL a new cushion TED (Thermo-Electric Device). REFER to Seat Cushion Thermo-Electric Device . CLEAR the DTCs. REPEAT the self-test.

DISCONNECT the battery ground cable. CONNECT driver seat safety belt buckle pretensioner C3049 and passenger seat safety belt buckle pretensioner C3050.

CONNECT driver seat side air bag module C3051 and passenger seat side air bag module C3052.

REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.

AT20 CHECK THE TED (Thermo-Electric Device) INSTALLATION AND FOR A CRUSHED SEAT BACKREST

- 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.

- Remove the seat. Refer to Seat- Front .

- Remove the seat backrest cover. Refer to Seat Backrest Cover- Front .

- Inspect the seat backrest for the following:
- Is the backrest blower obstructed?

- Is the blower filter restricted or plugged?

- Is the TED (Thermo-Electric Device) correctly installed?

- Is the seat backrest foam pad crushed or restricted?

- Is the climate controlled seat manifold crushed or restricted?

Is the TED (Thermo-Electric Device) correctly installed and are there no signs of damage to the foam pad and manifold?

Yes
GO to AT21.

No
CORRECTLY INSTALL the backrest TED (Thermo-Electric Device) or INSTALL a new seat backrest foam pad and/or climate controlled seat manifold. CONNECT the battery ground cable. CLEAR the DTCs. REPEAT the self-test.

REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.

AT21 CHECK THE CUSHION TED (Thermo-Electric Device) CIRCUIT FOR A SHORT TO VOLTAGE

- Disconnect: DCSM (Dual Climate Controlled Seat Module) C3265A.

- NOTE: Do not connect the safety belt buckle pretensioner or seat side air bag electrical connectors at this time.

Position the driver seat in the vehicle and connect the seat-to-floor connectors.

- Connect the battery ground cable.

- Ignition ON.

- Measure the voltage between DCSM (Dual Climate Controlled Seat Module) C3265A-H, circuit RHS02 (BU/OG), harness side and ground.

Is the voltage less than 0.5 volt?

Yes
GO to AT22.

No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.

DISCONNECT the battery ground cable. CONNECT driver seat safety belt buckle pretensioner C3049 and passenger seat safety belt buckle pretensioner C3050.

CONNECT driver seat side air bag module C3051 and passenger seat side air bag module C3052.

REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.

AT22 CHECK THE CUSHION TED (Thermo-Electric Device) CIRCUIT FOR A SHORT TO GROUND

- Ignition OFF.

- Measure the resistance between DCSM (Dual Climate Controlled Seat Module) C3265A-G, circuit CHS02 (YE/BU), harness side and ground.

Is the resistance greater than 10,000 ohms?

Yes
GO to AT23.

No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.

DISCONNECT the battery ground cable. CONNECT driver seat safety belt buckle pretensioner C3049 and passenger seat safety belt buckle pretensioner C3050.

CONNECT driver seat side air bag module C3051 and passenger seat side air bag module C3052.

REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.

AT23 CHECK RESISTANCE OF THE CUSHION TED (Thermo-Electric Device) AND WIRING

- Measure the resistance between DCSM (Dual Climate Controlled Seat Module) C3265A-G circuit CHS02 (YE/BU), harness side and DCSM (Dual Climate Controlled Seat Module) C3265A-H, circuit RHS02 (BU/OG), harness side.

Is the resistance between 0.9 and 10 ohms?

Yes
GO to AT25.

No
GO to AT24.

AT24 CHECK RESISTANCE OF THE CUSHION TED (Thermo-Electric Device)

- Disconnect: Cushion TED (Thermo-Electric Device) C3035.

- Measure the resistance between cushion TED (Thermo-Electric Device) C3035 pin 1 and pin 3, component side.

Is the resistance between 0.9 and 10 ohms?

Yes
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.

DISCONNECT the battery ground cable. CONNECT driver seat safety belt buckle pretensioner C3049 and passenger seat safety belt buckle pretensioner C3050.

CONNECT driver seat side air bag module C3051 and passenger seat side air bag module C3052.

REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.

No
INSTALL a new cushion TED (Thermo-Electric Device). REFER to Seat Cushion Thermo-Electric Device . CLEAR the DTCs. REPEAT the self-test.

DISCONNECT the battery ground cable. CONNECT driver seat safety belt buckle pretensioner C3049 and passenger seat safety belt buckle pretensioner C3050.

CONNECT driver seat side air bag module C3051 and passenger seat side air bag module C3052.

REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.

AT25 CHECK THE BLOWER AND SPEED CONTROL CIRCUITS FOR A SHORT TO VOLTAGE

- Disconnect: DCSM (Dual Climate Controlled Seat Module) C3265C.

- Ignition ON.

- Measure the voltage between:
- DCSM (Dual Climate Controlled Seat Module) C3265C-16, circuit CHS13 (VT/BN), harness side and ground.

- DCSM (Dual Climate Controlled Seat Module) C3265C-12, circuit CHS04 (YE/GY), harness side and ground.

Is voltage present on any circuit?

Yes
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.

DISCONNECT the battery ground cable. CONNECT driver seat safety belt buckle pretensioner C3049 and passenger seat safety belt buckle pretensioner C3050.

CONNECT driver seat side air bag module C3051 and passenger seat side air bag module C3052.

REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.

No
GO to AT26.

AT26 CHECK THE BLOWER AND SPEED CONTROL CIRCUITS FOR A SHORT TO GROUND

- Ignition OFF.

- Measure the resistance between:
- DCSM (Dual Climate Controlled Seat Module) C3265C-16, circuit CHS13 (VT/BN), harness side and ground.

- DCSM (Dual Climate Controlled Seat Module) C3265C-12, circuit CHS04 (YE/GY), harness side and ground.

Are the resistances greater than 10,000 ohms?

Yes
GO to AT27.

No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.

DISCONNECT the battery ground cable. CONNECT driver seat safety belt buckle pretensioner C3049 and passenger seat safety belt buckle pretensioner C3050.

CONNECT driver seat side air bag module C3051 and passenger seat side air bag module C3052.

REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.

AT27 CHECK THE BLOWER AND WIRING

- NOTICE: The ohmmeter must be connected with the positive lead to Dual Climate Controlled Seat Module (DCSM) C3265C-16, circuit CHS13 (VT/BN) and the negative lead to DCSM (Dual Climate Controlled Seat Module) C3265C-15, circuit CHS03 (GN/BN) when measuring. Ohmmeter leads incorrectly connected will result in false readings and lead to incorrect identification of components that are not faulty.

Measure the resistance between DCSM (Dual Climate Controlled Seat Module) C3265C-16, circuit CHS13 (VT/BN), harness side and DCSM (Dual Climate Controlled Seat Module) C3265C-15, circuit CHS03 (GN/BN), harness side.

Is the resistance between 4,000 ohms and 10,000 ohms?

Yes
GO to AT29.

No
GO to AT28.

AT28 CHECK THE BLOWER

- Disconnect: Backrest TED (Thermo-Electric Device) C3034.

- 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 will result in false readings and lead to incorrect identification of components that are not faulty.

Measure the resistance between backrest TED (Thermo-Electric Device) C3034 pin 2 and pin 4, component side.

Is the resistance between 4,000 ohms and 10,000 ohms?

Yes
REPAIR the affected circuit(s). CLEAR the DTCs. REPEAT the self-test.

DISCONNECT the battery ground cable. CONNECT driver seat safety belt buckle pretensioner C3049 and passenger seat safety belt buckle pretensioner C3050.

CONNECT driver seat side air bag module C3051 and passenger seat side air bag module C3052.

REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.

No
INSTALL a new 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 driver seat safety belt buckle pretensioner C3049 and passenger seat safety belt buckle pretensioner C3050.

CONNECT driver seat side air bag module C3051 and passenger seat side air bag module C3052.

REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.

AT29 CHECK THE BLOWER SPEED CONTROL AND CIRCUIT

- NOTICE: The ohmmeter must be connected with the positive lead to C3265C-12, circuit CHS04 (YE/GY), harness side and the negative lead to C3265C-15, circuit CHS03 (GN/BN), harness side when measuring. Ohmmeter leads incorrectly connected will result in false readings and lead to incorrect identification of components that are not faulty.

Measure the resistance between DCSM (Dual Climate Controlled Seat Module) C3265C-12, circuit CHS04 (YE/GY) harness side and DCSM (Dual Climate Controlled Seat Module) C3265C-15, circuit CHS03 (GN/BN), harness side.

Is the resistance between 240K ohms and 4M ohms?

Yes
GO to AT31.

No
GO to AT30.

AT30 CHECK THE BLOWER SPEED CONTROL

- Disconnect: Backrest TED (Thermo-Electric Device) C3034.

- 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 will result in false readings and lead to incorrect identification of components that are not faulty.

Measure the resistance between backrest TED (Thermo-Electric Device) C3034 pin 7 and pin 4, component side.

Is the resistance between 240K ohms and 4M ohms?

Yes
REPAIR the affected circuit(s). CLEAR the DTCs. REPEAT the self-test.

DISCONNECT the battery ground cable. CONNECT driver seat safety belt buckle pretensioner C3049 and passenger seat safety belt buckle pretensioner C3050.

CONNECT driver seat side air bag module C3051 and passenger seat side air bag module C3052.

REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.

No
INSTALL a new 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 driver seat safety belt buckle pretensioner C3049 and passenger seat safety belt buckle pretensioner C3050.

CONNECT driver seat side air bag module C3051 and passenger seat side air bag module C3052.

REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.

AT31 CHECK THE THERMISTOR CIRCUIT FOR A SHORT TO VOLTAGE

- 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: Driver Seat Safety Belt Buckle Pretensioner C3049 and Passenger Seat Safety Belt Buckle Pretensioner C3050.

- Disconnect: Driver Seat Side Air Bag C3051 and Passenger Seat Side Air Bag C3052.

- 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.

- Ignition ON.

- Measure the voltage between DCSM (Dual Climate Controlled Seat Module) C3265B-9, circuit VHS35 (VT/OG), harness side and ground.

Is the voltage less than 0.5 volt?

Yes
GO to AT32.

No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.

DISCONNECT the battery ground cable. CONNECT driver seat safety belt buckle pretensioner C3049 and passenger seat safety belt buckle pretensioner C3050.

CONNECT driver seat side air bag module C3051 and passenger seat side air bag module C3052.

REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.

AT32 CHECK THE THERMISTOR CIRCUIT FOR A SHORT TO GROUND

- Ignition OFF.

- Measure the resistance between DCSM (Dual Climate Controlled Seat Module) C3265B-9, circuit VHS35 (VT/OG), harness side and ground.

Is the resistance greater than 10,000 volts?

Yes
GO to AT33.

No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.

DISCONNECT the battery ground cable. CONNECT driver seat safety belt buckle pretensioner C3049 and passenger seat safety belt buckle pretensioner C3050.

CONNECT driver seat side air bag module C3051 and passenger seat side air bag module C3052.

REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.

AT33 CHECK THE THERMISTOR AND WIRING

- Measure the resistance between DCSM (Dual Climate Controlled Seat Module) C3265B-9, circuit VHS35 (VT/OG), harness side and DCSM (Dual Climate Controlled Seat Module) C3265B-10, circuit RHS15 (GY/BN), 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
INSTALL a new DCSM (Dual Climate Controlled Seat Module). REFER to Dual Climate Controlled Seat Module (DCSM) . CLEAR the DTCs. REPEAT the self-test.

DISCONNECT the battery ground cable. CONNECT driver seat safety belt buckle pretensioner C3049 and passenger seat safety belt buckle pretensioner C3050.

CONNECT driver seat side air bag module C3051 and passenger seat side air bag module C3052.

REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.

No
GO to AT34.

AT34 CHECK THE THERMISTOR

- Disconnect: Backrest TED (Thermo-Electric Device) C3034.

- Measure the resistance between backrest TED (Thermo-Electric Device) 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