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Pinpoint Test AI: DTC B272F




Seats

Pinpoint Tests

Pinpoint Test AI: DTC B272F

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

Normal Operation

The passenger climate controlled seat blowers are located within the backrest and cushion Thermo-Electric Devices (TEDs). The Dual Climate Controlled Seat Module (DCSM) supplies voltage and ground to both blowers. The blowers are independently controlled by separate speed control circuits from the DCSM.

- DTC B272F (Passenger Ignition Run/Blower Circuit Short to Ground) - If either the blower voltage supply or return circuits are open (to both cushion and backrest blowers) or shorted to voltage, the DTC is set and after 4-6 seconds the DCSM disables outputs to the passenger seat. The DTC also sets if the blower voltage supply or return circuit is open to only one blower when DCSM supply voltage is less than 12 volts.

This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- HVAC module
- Backrest or cushion TED
- DCSM

PINPOINT TEST AI: DTC B272F

NOTICE: Use the correct probe adapter(s) from the Flex Probe Kit when taking measurements. Failure to use the correct probe adapter(s) may damage the connector.

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.

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AI1 CHECK THE TED BLOWER MOTOR CIRCUITS FOR A SHORT TO VOLTAGE

NOTE: If a seat equipped with a seat mounted side air bag is being serviced, the Supplemental Restraint System (SRS) must be depowered. Refer to Supplemental Restraint System Supplemental Restraint System (SRS) Depowering and Repowering.

NOTE: The air bag warning lamp illuminates when the Restraints Control Module (RCM) fuse is removed and the ignition switch is ON. This is normal operation and does not indicate an SRS fault.

NOTE: The SRS must be fully operational and free of faults before releasing the vehicle to the customer.

- Ignition OFF.

- 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.

- For vehicles equipped with seat side air bags, carry out the following:
- Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering in the General Procedures portion of Supplemental Restraint System Supplemental Restraint System (SRS) Depowering and Repowering.
- Disconnect the passenger seat side air bag module C339.
- Connect the battery ground cable. Refer to Battery, Mounting and Cables Battery Disconnect / Connect.
- Disconnect: DCSM C3265C.
- Disconnect: Passenger Cushion TED C3040.
- Disconnect: Passenger Backrest TED C3039.
- Ignition ON.
- Measure the voltage between DCSM C3265C, harness side and ground using the following chart.








- Is any voltage present on either circuit?

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

For vehicles equipped with seat side air bags, DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C339. REPOWER the SRS. REFER to Supplemental Restraint System Supplemental Restraint System (SRS) Depowering and Repowering.

No
GO to AI2.

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AI2 CHECK THE PASSENGER TED BLOWER MOTOR CIRCUITS FOR AN OPEN

- Ignition OFF.
- Measure the resistance between DCSM C3265C pins, harness side and cushion TED C3040 pins, harness side using the following chart.








- Are the resistances less than 5 ohms?

Yes
GO to AI3.

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

For vehicles equipped with seat side air bags, DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C339. REPOWER the SRS. REFER to Supplemental Restraint System Supplemental Restraint System (SRS) Depowering and Repowering.

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AI3 CHECK THE RESISTANCE OF THE PASSENGER CUSHION AND BACKREST TED BLOWER MOTORS

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

- Measure the resistance between:
- passenger cushion TED C3040 pins 2 and 4, component side.
- passenger backrest TED C3039 pins 2 and 4, component side.




- Are the resistances between 4,000 and 10,000 ohms?

Yes
GO to AI4.

No
If the passenger cushion TED resistance is not between 4,000 and 10,000 ohms, INSTALL a new passenger cushion TED. REFER to Seat Cushion - Front, Bucket Seat Bucket Seat. CLEAR the DTCs. REPEAT the self-test.

For vehicles equipped with seat side air bags, DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C339. REPOWER the SRS. REFER to Supplemental Restraint System Supplemental Restraint System (SRS) Depowering and Repowering. If the passenger backrest TED resistance is not between 4,000 and 10,000 ohms, INSTALL a new passenger backrest TED. REFER to Seat Backrest - Front, Bucket Seat Bucket Seat. CLEAR the DTCs. REPEAT the self-test.

For vehicles equipped with seat side air bags, DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C339. REPOWER the SRS. REFER to Supplemental Restraint System Supplemental Restraint System (SRS) Depowering and Repowering.

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AI4 CHECK FOR CORRECT DCSM OPERATION

- Disconnect all the DCSM electrical connectors.
- Check the harness and component side connectors for the following:

- corrosion.
- damaged pins.
- pushed-out pins.
- Connect all the DCSM electrical connectors and make sure they seat correctly.
- Start the engine.
- Operate the climate controlled seats and verify system operation.
- CLEAR all CMDTCs.
- Enter the following diagnostic mode on the scan tool: Self Test - DCSM.
- Is DTC B272F still present?

Yes
INSTALL a new DCSM. REFER to Dual Climate Controlled Seat Module (DCSM) Service and Repair. CLEAR all CMDTCs. REPEAT the self-test.

For vehicles equipped with seat side air bags, DISCONNECT the battery ground cable. CONNECT driver seat side air bag module C3051 and passenger seat side air bag module C339. REPOWER the SRS. REFER to Supplemental Restraint System Supplemental Restraint System (SRS) Depowering and Repowering.

No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR all CMDTCs. REPEAT the self-test.

For vehicles equipped with seat side air bags, DISCONNECT the battery ground cable. CONNECT driver seat side air bag module C3051 and passenger seat side air bag module C339. REPOWER the SRS. REFER to Supplemental Restraint System Supplemental Restraint System (SRS) Depowering and Repowering.

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