Part 2

Seats

Pinpoint Tests

Pinpoint Test AL: DTC B272C

Refer to Wiring Diagram Set 119, Climate Controlled Seats for schematic and connector information. Diagrams By Number

Normal Operation

Climate controlled seats are independently controlled 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, diagnostic testing can be carried out with the ignition ON. The system receives voltage from Battery Junction Box (BJB) fuse 22 (30A) supplying voltage into DCSM C3265a pins E and F, circuit CBX01 (GN/RD). If voltage is disconnected from either pin E or F of DCSM C3265a both seats will remain operational because the voltage supply circuits are connected internally in the DCSM. However, if a fault occurs setting a DTC specific to either climate controlled seat, only the affected seat will be disabled by the DCSM.

The seat cushion and backrest are equipped with a Thermo-Electric Device (TED) assembly that includes a seat blower (fan motor, serviced as an assembly with the TED). Cabin air is drawn through the blower and distributed to each of the TED modules. The TEDs 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 uses a set of flexible algorithms to control the heating/cooling modes and the blower speed dependant on the HVAC module seat switch settings.

A differential fault occurs when the cushion and backrest TEDs on an affected seat are reporting very different temperatures to the DCSM. This may result from an airflow restriction or a circuit fault of either TED area. If a TED and manifold is clear of obstruction and is operational, the other TED and circuitry on the seat should be checked. It is important to note that a TED with a higher temperature may be operating correctly and not the area of concern. The other TED 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 of 60°C (108°F) or more for more than 4 seconds, the TED is disconnected or the duct is blocked, this DTC will set. When this happens the first time in a key cycle, the DCSM puts the driver seat system into recovery mode (see 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 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 filter
- Crushed or restricted cushion or backrest foam pad
- Crushed or restricted cushion or backrest climate controlled seat manifold
- Cushion or backrest TED assembly
- DCSM

PINPOINT TEST AL: DTC B272C

NOTICE: When taking measurements at Dual Climate Controlled Seat Module (DCSM) harness connectors, do not insert the electrical probes into the female connector pins. Inserting the probes into connector pins can cause intermittent or open electrical connections after reassembly resulting in Diagnostic Trouble Codes (DTCs) and system failure. Touching the tip of these connector pins is recommended instead.

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.

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AL18 CHECK THE TED THERMISTOR AND WIRING RESISTANCE AT THE DCSM

- Measure the resistance between DCSM C3265b-7, circuit VHS26 (VT), harness side and DCSM C3265b-8, circuit RHS05 (YE/VT), harness side. Note the ambient temperature and compare result to the following table:

- Is the resistance within the limits indicated?

Yes
INSTALL a new DCSM. REFER to Dual Climate Controlled Seat Module (DCSM) Dual Climate Controlled Seat Module (DCSM). CLEAR the DTCs. REPEAT the self-test.

DISCONNECT the battery ground cable.

CONNECT passenger safety belt buckle pretensioner C3066.

CONNECT passenger seat side air bag module C3133.

CONNECT driver safety belt buckle pretensioner C3065.

CONNECT driver seat side air bag module C3134.

REPOWER the SRS. REFER to Restraint Systems.

No
GO to AL19.

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AL19 CHECK THE TED THERMISTOR RESISTANCE

- Disconnect: Cushion TED C3035.
- Measure the resistance between cushion TED pin 5 and pin 8, component side. Note the ambient temperature and compare result to the following table:

- Is the resistance within the limits indicated?

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

DISCONNECT the battery ground cable.

CONNECT passenger safety belt buckle pretensioner C3066.

CONNECT passenger seat side air bag module C3133.

CONNECT driver safety belt buckle pretensioner C3065.

CONNECT driver seat side air bag module C3134.

REPOWER the SRS. REFER to Restraint Systems.

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

DISCONNECT the battery ground cable.

CONNECT passenger safety belt buckle pretensioner C3066.

CONNECT passenger seat side air bag module C3133.

CONNECT driver safety belt buckle pretensioner C3065.

CONNECT driver seat side air bag module C3134.

REPOWER the SRS. REFER to Restraint Systems.

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AL20 CHECK FOR CORRECT TED INSTALLATION AND FOR CRUSHED FOAM

- Ignition OFF.
- Remove the seat. Refer to Seat - Front Seat - Front.
- Remove the seat backrest trim cover. Refer to Seat Backrest Cover - Front 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 correctly installed?
- Is the seat backrest foam pad crushed or restricted?
- Is the climate controlled seat manifold crushed or restricted?
- Is the TED correctly installed and the foam pad and manifold OK?

Yes
GO to AL21.

No
CORRECTLY install the backrest TED or INSTALL a new seat backrest foam pad and/or climate controlled seat manifold.

INSTALL the seat. REFER to Seat - Front Seat - Front.

CLEAR the DTCs. REPEAT the self-test.

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AL21 CHECK CUSHION TED CIRCUIT FOR A SHORT TO VOLTAGE

- Ignition OFF.
- Position the driver seat in the vehicle and connect the seat-to-floor connectors.
- Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering in the General Procedures portion of Restraint Systems.
- Disconnect: Driver Seat Side Air Bag C3134.
- Disconnect: Driver Safety Belt Buckle Pretensioner C3065.
- Disconnect: Passenger Seat Side Air Bag C3133.
- Disconnect: Passenger Safety Belt Buckle Pretensioner C3066.
- Disconnect: DCSM C3265a.
- 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 DCSM C3265a-H, circuit RHS02 (BU/OG), harness side and ground.

- Is the resistance greater than 10,000 ohms?

Yes
GO to AL23.

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

DISCONNECT the battery ground cable.

CONNECT passenger safety belt buckle pretensioner C3066.

CONNECT passenger seat side air bag module C3133.

CONNECT driver safety belt buckle pretensioner C3065.

CONNECT driver seat side air bag module C3134.

REPOWER the SRS. REFER to Restraint Systems.

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AL23 CHECK THE RESISTANCE OF THE CUSHION TED AND WIRING

- Measure the resistance between DCSM C3265a-G circuit CHS02 (YE/BU), harness side and DCSM C3265a-H, circuit RHS02 (BU/OG), harness side.

- Is the resistance between 0.9 and 10 ohms?

Yes
GO to AL25.

No
GO to AL24.

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AL24 CHECK THE CUSHION TED RESISTANCE

- Disconnect: Cushion TED C3035.
- Measure the resistance between cushion TED C3035 pin 1 and pin 3, component side.

- Is the resistance between 0.9 and 10 ohms?

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

DISCONNECT the battery ground cable.

CONNECT passenger safety belt buckle pretensioner C3066.

CONNECT passenger seat side air bag module C3133.

CONNECT driver safety belt buckle pretensioner C3065.

CONNECT driver seat side air bag module C3134.

REPOWER the SRS. REFER to Restraint Systems.

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

DISCONNECT the battery ground cable.

CONNECT passenger safety belt buckle pretensioner C3066.

CONNECT passenger seat side air bag module C3133.

CONNECT driver safety belt buckle pretensioner C3065.

CONNECT driver seat side air bag module C3134.

REPOWER the SRS. REFER to Restraint Systems.

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AL25 CHECK BLOWER CIRCUIT AND SPEED CONTROL CIRCUIT FOR A SHORT TO VOLTAGE

- Disconnect: DCSM C3265c.
- Ignition ON.
- Measure the voltage between:
- DCSM C3265c-16, circuit CHS03 (GN/BN), harness side and ground.
- DCSM C3265c-12, circuit VHS16 (BU/GN), harness side and ground.

- Is voltage present on either circuit?

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

DISCONNECT the battery ground cable.

CONNECT passenger safety belt buckle pretensioner C3066.

CONNECT passenger seat side air bag module C3133.

CONNECT driver safety belt buckle pretensioner C3065.

CONNECT driver seat side air bag module C3134.

REPOWER the SRS. REFER to Restraint Systems.

No
GO to AL26.

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AL26 CHECK BLOWER AND SPEED CONTROL CIRCUITS FOR A SHORT TO GROUND

- Ignition OFF.
- Measure the resistance between:
- DCSM C3265c-16, circuit CHS03 (GN/BN), harness side and ground.
- DCSM C3265c-12, circuit VHS16 (BU/GN), harness side and ground.

- Are the resistances greater than 10,000 ohms?

Yes
GO to AL27.

No
REPAIR the circuit(s). CLEAR the DTCs. REPEAT the self-test.

DISCONNECT the battery ground cable.

CONNECT passenger safety belt buckle pretensioner C3066.

CONNECT passenger seat side air bag module C3133.

CONNECT driver safety belt buckle pretensioner C3065.

CONNECT driver seat side air bag module C3134.

REPOWER the SRS. REFER to Restraint Systems.

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AL27 CHECK THE BLOWER AND WIRING RESISTANCE

- NOTE: The ohmmeter must be connected with the positive lead to DCSM C3265c-16, circuit CHS03 (GN/BN) and the negative lead to DCSM C3265c-15, circuit RHS03 (GY/OG) 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 C3265c-16, circuit CHS03 (GN/BN), harness side and DCSM C3265c-15, circuit RHS03 (GY/OG), harness side.

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

Yes
GO to AL29.

No
GO to AL28.

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AL28 CHECK THE BLOWER RESISTANCE

- Disconnect: Backrest TED C3034.
- NOTE: 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 C3034 pin 2 and pin 4, component side.

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

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

DISCONNECT the battery ground cable.

CONNECT passenger safety belt buckle pretensioner C3066.

CONNECT passenger seat side air bag module C3133.

CONNECT driver safety belt buckle pretensioner C3065.

CONNECT driver seat side air bag module C3134.

REPOWER the SRS. REFER to Restraint Systems.

No
INSTALL a new backrest TED. REFER to Seat Backrest Thermo-Electric Device Seat Backrest Thermo-Electric Device. CLEAR the DTCs. REPEAT the self-test.

DISCONNECT the battery ground cable.

CONNECT passenger safety belt buckle pretensioner C3066.

CONNECT passenger seat side air bag module C3133.

CONNECT driver safety belt buckle pretensioner C3065.

CONNECT driver seat side air bag module C3134.

REPOWER the SRS. REFER to Restraint Systems.

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AL29 CHECK THE BLOWER SPEED CONTROL AND CIRCUIT RESISTANCE

- NOTE: The ohmmeter must be connected with the positive lead to C3265c-12, circuit VHS16 (BU/GN), harness side and the negative lead to C3265c-15, circuit RHS03 (GY/OG), 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 C3265c-12, circuit VHS16 (BU/GN) harness side and DCSM C3265c-15, circuit RHS03 (GY/OG), harness side.

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

Yes
GO to AL31.

No
GO to AL30.

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AL30 CHECK THE BLOWER SPEED CONTROL RESISTANCE

- Disconnect: Backrest TED C3034.
- NOTE: 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 C3034 pin 7 and pin 4, component side.

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

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

DISCONNECT the battery ground cable.

CONNECT passenger safety belt buckle pretensioner C3066.

CONNECT passenger seat side air bag module C3133.

CONNECT driver safety belt buckle pretensioner C3065.

CONNECT driver seat side air bag module C3134.

REPOWER the SRS. REFER to Restraint Systems.

No
INSTALL a new backrest TED. REFER to Seat Backrest Thermo-Electric Device Seat Backrest Thermo-Electric Device. CLEAR the DTCs. REPEAT the self-test.

DISCONNECT the battery ground cable.

CONNECT passenger safety belt buckle pretensioner C3066.

CONNECT passenger seat side air bag module C3133.

CONNECT driver safety belt buckle pretensioner C3065.

CONNECT driver seat side air bag module C3134.

REPOWER the SRS. REFER to Restraint Systems.

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AL31 CHECK THERMISTOR CIRCUIT FOR A SHORT TO VOLTAGE

- Disconnect: DCSM C3265b.
- Ignition ON.
- Measure the voltage between DCSM C3265b-9, circuit VHS35 (VT/OG), 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 safety belt buckle pretensioner C3066.

CONNECT passenger seat side air bag module C3133.

CONNECT driver safety belt buckle pretensioner C3065.

CONNECT driver seat side air bag module C3134.

REPOWER the SRS. REFER to Restraint Systems.

No
GO to AL32.

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AL32 CHECK THERMISTOR CIRCUIT FOR A SHORT TO GROUND

- Ignition OFF.
- Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering in the General Procedures portion of Restraint Systems.
- Disconnect: Driver Seat Side Air Bag C3134.
- Disconnect: Driver Safety Belt Buckle Pretensioner C3065.
- Disconnect: Passenger Seat Side Air Bag C3133.
- Disconnect: Passenger Safety Belt Buckle Pretensioner C3066.
- Disconnect: DCSM C3265b.
- Measure the resistance between DCSM C3265b-9, circuit VHS35 (VT/OG), harness side and ground.

- Is the resistance greater than 10,000 ohms?

Yes
GO to AL33.

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

DISCONNECT the battery ground cable.

CONNECT passenger safety belt buckle pretensioner C3066.

CONNECT passenger seat side air bag module C3133.

CONNECT driver safety belt buckle pretensioner C3065.

CONNECT driver seat side air bag module C3134.

REPOWER the SRS. REFER to Restraint Systems.

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AL33 CHECK THE TED THERMISTOR AND WIRING RESISTANCE

- Measure the resistance between DCSM C3265b-9, circuit VHS35 (VT/OG), harness side and DCSM C3265b-10, circuit RHS15 (GY/BN), harness side. Note the ambient temperature and compare result to the following table:

- Is the resistance within the limits indicated?

Yes
INSTALL a new DCSM. REFER to Dual Climate Controlled Seat Module (DCSM) Dual Climate Controlled Seat Module (DCSM). CLEAR the DTCs. REPEAT the self-test.

DISCONNECT the battery ground cable.

CONNECT passenger safety belt buckle pretensioner C3066.

CONNECT passenger seat side air bag module C3133.

CONNECT driver safety belt buckle pretensioner C3065.

CONNECT driver seat side air bag module C3134.

REPOWER the SRS. REFER to Restraint Systems.

No
GO to AL34.

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AL34 CHECK THE TED THERMISTOR RESISTANCE

- Disconnect: Backrest TED C3034.
- Measure the resistance between backrest TED pin 5 and pin 8, component side. Note the ambient temperature and compare result to the following table: