Part 2
Seats
Pinpoint Tests
Pinpoint Test AT: DTC B272C
Refer to Wiring Diagram Set 119, Climate Controlled Seats for schematic and connector information. Diagrams By Number
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, diagnostic testing can be carried out with the ignition switch ON and the engine OFF. The system receives voltage from Battery Junction Box (BJB) fuse 16 (30A) supplying battery voltage on circuit SBB16 (VT/RD) into DCSM C3036a pins E and F. If voltage is disconnected from either pin E or F of DCSM C3036a with the connection remaining on the other circuit, both seats will remain operational because the 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 and the other will remain operational.
Each driver and front passenger 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 located in the seat cushion and backrest. 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 the seat are reporting temperatures to the DCSM with a difference between them of 60°C (108°F) or greater. This can result from an air flow restriction or a circuit fault of either TED. 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 be 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. Principles of Operation
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 AT: 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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AT18 CHECK THE THERMISTOR AND WIRING
- Measure the resistance between DCSM C3036b-7, circuit VHS26 (VT), harness side and DCSM C3036b-8, circuit RHS05 (YE/VT), harness side. Note the ambient temperature and refer 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). REPEAT the self-test. CLEAR the DTCs.
DISCONNECT the battery ground cable.
CONNECT passenger seat side air bag module C327.
CONNECT driver seat side air bag module C328.
REPOWER the SRS. REFER to Restraint Systems.
No
GO to AT19.
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AT19 CHECK THE THERMISTOR
- Disconnect: Cushion TED C3327.
- Measure the resistance between cushion TED pin 5 and pin 8, component side. Note the ambient temperature and refer to the following table.
- Is the resistance within the limits indicated?
Yes
REPAIR the affected circuit(s). REPEAT the self-test. CLEAR the DTCs.
DISCONNECT the battery ground cable.
CONNECT passenger seat side air bag module C327.
CONNECT driver seat side air bag module C328.
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. REPEAT the self-test. CLEAR the DTCs.
DISCONNECT the battery ground cable.
CONNECT passenger seat side air bag module C327.
CONNECT driver seat side air bag module C328.
REPOWER the SRS. REFER to Restraint Systems.
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AT20 CHECK THE TED INSTALLATION AND FOR A CRUSHED SEAT BACKREST
- Ignition OFF.
- Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering in the General Procedures portion of Restraint Systems.
- Remove the seat. Refer to Seat - Front Seat - Front.
- Remove the seat backrest cover. Refer to Seat Backrest Cover - Front, Without Fold Flat Seat Backrest Cover - Front, Without Fold Flat.
- 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 are there no signs of damage to the foam pad and manifold?
Yes
GO to AT21.
No
Correctly INSTALL the backrest TED or INSTALL a new seat backrest foam pad and/or climate controlled seat manifold. CONNECT the battery ground cable. REPEAT the self-test. CLEAR the DTCs.
REPOWER the SRS. REFER to Restraint Systems.
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AT21 CHECK THE CUSHION TED CIRCUIT RHS02 (BU/OG) FOR A SHORT TO VOLTAGE
- 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 C327.
- Disconnect: DCSM C3036a.
- NOTE: Do not connect the seat side air bag electrical connector at this time.
- Position the driver seat in the vehicle and connect the seat-to-floor connectors.
- 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 C3036a-H, circuit RHS02 (BU/OG), harness side and ground.
- Is any voltage present?
Yes
REPAIR the circuit. REPEAT the self-test. CLEAR the DTCs.
DISCONNECT the battery ground cable.
CONNECT passenger seat side air bag module C327.
CONNECT driver seat side air bag module C328.
REPOWER the SRS. REFER to Restraint Systems.
No
GO to AT22.
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AT22 CHECK CUSHION TED CIRCUIT CHS02 (YE/BU) FOR SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between DCSM C3036a-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. REPEAT the self-test. CLEAR the DTCs.
DISCONNECT the battery ground cable.
CONNECT passenger seat side air bag module C327.
CONNECT driver seat side air bag module C328.
REPOWER the SRS. REFER to Restraint Systems.
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AT23 CHECK THE RESISTANCE OF THE CUSHION TED AND WIRING
- Measure the resistance between DCSM C3036a-G circuit CHS02 (YE/BU), harness side and DCSM C3036a-H, circuit RHS02 (BU/OG), harness side.
- Is the resistance between 0.9 and 10 ohms?
Yes
GO to AT25.
No
GO to AT24.
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AT24 CHECK THE RESISTANCE OF THE CUSHION TED
- Disconnect: Cushion TED C3327.
- Measure the resistance between cushion TED C3327 pin 1 and pin 3, component side.
- Is the resistance between 0.9 and 10 ohms?
Yes
REPAIR the circuit. REPEAT the self-test. CLEAR the DTCs.
DISCONNECT the battery ground cable.
CONNECT passenger seat side air bag module C327.
CONNECT driver seat side air bag module C328.
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. REPEAT the self-test. CLEAR the DTCs.
DISCONNECT the battery ground cable.
CONNECT passenger seat side air bag module C327.
CONNECT driver seat side air bag module C328.
REPOWER the SRS. REFER to Restraint Systems.
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AT25 CHECK THE BLOWER AND SPEED CONTROL CIRCUITS FOR A SHORT TO VOLTAGE
- Disconnect: DCSM C3036c.
- Ignition ON.
- Measure the voltage between:
- DCSM C3036c-16, circuit CHS03 (GN/BN), harness side and ground.
- DCSM C3036c-12, circuit VHS16 (BU/GN), harness side and ground.
- Is voltage present on either circuit?
Yes
REPAIR the circuit. REPEAT the self-test. CLEAR the DTCs.
DISCONNECT the battery ground cable.
CONNECT passenger seat side air bag module C327.
CONNECT driver seat side air bag module C328.
REPOWER the SRS. REFER to Restraint Systems.
No
GO to AT26.
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AT26 CHECK THE BLOWER AND SPEED CONTROL CIRCUITS FOR A SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between:
- DCSM C3036c-16, circuit CHS03 (GN/BN), harness side and ground.
- DCSM C3036c-12, circuit VHS16 (BU/GN), harness side and ground.
- Are the resistances greater than 10,000 ohms?
Yes
GO to AT27.
No
REPAIR the circuit. REPEAT the self-test. CLEAR the DTCs.
DISCONNECT the battery ground cable.
CONNECT passenger seat side air bag module C327.
CONNECT driver seat side air bag module C328.
REPOWER the SRS. REFER to Restraint Systems.
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AT27 CHECK THE BLOWER AND WIRING
- NOTICE: The ohmmeter must be connected with the positive lead to Dual Climate Controlled Seat Module (DCSM) C3036c-16, circuit CHS03 (GN/BN) and the negative lead to DCSM C3036c-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 C3036c-16, circuit CHS03 (GN/BN), harness side and DCSM C3036c-15, circuit RHS03 (GY/OG), harness side.
- Is the resistance between 4,000 ohms and 10,000 ohms?
Yes
GO to AT29.
No
GO to AT28.
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AT28 CHECK THE BLOWER
- Disconnect: Backrest TED C3322.
- 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 C3322 pin 2 and pin 4, component side.
- Is the resistance between 4,000 ohms and 10,000 ohms?
Yes
REPAIR the affected circuit(s). REPEAT the self-test. CLEAR the DTCs.
DISCONNECT the battery ground cable.
CONNECT passenger seat side air bag module C327.
CONNECT driver seat side air bag module C328.
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. REPEAT the self-test. CLEAR the DTCs.
DISCONNECT the battery ground cable.
CONNECT passenger seat side air bag module C327.
CONNECT driver seat side air bag module C328.
REPOWER the SRS. REFER to Restraint Systems.
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AT29 CHECK BLOWER SPEED CONTROL AND CIRCUIT
- NOTICE: The ohmmeter must be connected with the positive lead to C3036c-12, circuit VHS16 (BU/GN), harness side and the negative lead to C3036c-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 C3036c-12, circuit VHS16 (BU/GN), harness side and DCSM C3036c-15, circuit RHS03 (GY/OG), harness side.
- Is the resistance between 240,000 ohms and 420,000 ohms?
Yes
GO to AT31.
No
GO to AT30.
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AT30 CHECK THE BLOWER SPEED CONTROL
- Disconnect: Backrest TED C3322.
- 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 C3322 pin 7 and pin 4, component side.
- Is the resistance between 240,000 ohms and 420,000 ohms?
Yes
REPAIR the affected circuit(s). REPEAT the self-test. CLEAR the DTCs.
DISCONNECT the battery ground cable.
CONNECT passenger seat side air bag module C327.
CONNECT driver seat side air bag module C328.
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. REPEAT the self-test. CLEAR the DTCs.
DISCONNECT the battery ground cable.
CONNECT passenger seat side air bag module C327.
CONNECT driver seat side air bag module C328.
REPOWER the SRS. REFER to Restraint Systems.
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AT31 CHECK THERMISTOR CIRCUIT FOR A SHORT TO VOLTAGE
- 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 C328.
- Disconnect: Passenger Seat Side Air Bag C327.
- Disconnect: DCSM C3036b.
- 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 C3036b-9, circuit VHS35 (VT/OG), harness side and ground.
- Is any voltage present?
Yes
REPAIR the circuit. REPEAT the self-test. CLEAR the DTCs.
DISCONNECT the battery ground cable.
CONNECT passenger seat side air bag module C327.
CONNECT driver seat side air bag module C328.
REPOWER the SRS. REFER to Restraint Systems.
No
GO to AT32.
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AT32 CHECK THERMISTOR CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between DCSM C3036b-9, circuit VHS35 (VT/OG), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to AT33.
No
REPAIR the circuit. REPEAT the self-test. CLEAR the DTCs.
DISCONNECT the battery ground cable.
CONNECT passenger seat side air bag module C327.
CONNECT driver seat side air bag module C328.
REPOWER the SRS. REFER to Restraint Systems.
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AT33 CHECK THE THERMISTOR AND WIRING
- Measure the resistance between DCSM C3036b-9, circuit VHS35 (VT/OG), harness side and DCSM C3036b-10, circuit RHS15 (GY/BN), harness side. Note the ambient temperature and refer 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). REPEAT the self-test. CLEAR the DTCs.
DISCONNECT the battery ground cable.
CONNECT passenger seat side air bag module C327.
CONNECT driver seat side air bag module C328.
REPOWER the SRS. REFER to Restraint Systems.
No
GO to AT34.
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AT34 CHECK THE THERMISTOR
- Disconnect: Backrest TED C3322.
- Measure the resistance between backrest TED pin 5 and pin 8, component side. Note the ambient temperature and refer to the following table.
- Is the resistance within the limits indicated?
Yes
REPAIR the affected circuit(s). REPEAT the self-test. CLEAR the DTCs.
DISCONNECT the battery ground cable.
CONNECT passenger seat side air bag module C327.
CONNECT driver seat side air bag module C328.
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. REPEAT the self-test. CLEAR the DTCs.
DISCONNECT the battery ground cable.
CONNECT passenger seat side air bag module C327.
CONNECT driver seat side air bag module C328.
REPOWER the SRS. REFER to Restraint Systems.
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