Pinpoint Test AT: DTC B272F
Seats
Pinpoint Test AT: DTC B272F
NOTE: This DTC sets for an open or short to voltage. See DTC setting description below.
Refer to Wiring Diagram Set 119, Climate Controlled Seats for schematic and connector information Electrical Diagrams.
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 (Dual Climate Controlled Seat Module).
- 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 (Dual Climate Controlled Seat Module) 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 (Dual Climate Controlled Seat Module) supply voltage is less than 12 volts.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Backrest or cushion TED (Thermo-Electric Device)
- DCSM (Dual Climate Controlled Seat Module)
PINPOINT TEST AT : DTC B272F
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: If a seat equipped with a seat mounted side air bag is being serviced, the Supplemental Restraint System (SRS) must be depowered. Refer to Restraints and Safety Systems &/or Air Bag Systems.
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 (Supplemental Restraint System) fault.
NOTE: The SRS (Supplemental Restraint System) must be fully operational and free of faults before releasing the vehicle to the customer.
AT1 CHECK THE TED (Thermo-Electric Device) BLOWER MOTOR CIRCUITS 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: Passenger Seat Side Air Bag C327.
- Disconnect: DCSM (Dual Climate Controlled Seat Module) C3036C.
- Disconnect: Passenger Cushion TED (Thermo-Electric Device) C3328.
- Disconnect: Passenger Backrest TED (Thermo-Electric Device) C3326.
- 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) C3036C, harness side and ground using the following chart:
DCSM (Dual Climate Controlled Seat Module) Connector Circuit C3036C-7 RHS08 (VT/WH) C3036C-8 CHS08 (BN/YE)
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 C327.
REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
No
GO to AT2.
AT2 CHECK THE PASSENGER TED (Thermo-Electric Device) BLOWER MOTOR CIRCUITS FOR AN OPEN
- Measure the resistance between:
- DCSM (Dual Climate Controlled Seat Module) C3036C-8, circuit CHS08 (BN/YE), harness side and passenger cushion TED (Thermo-Electric Device) C3328-2, circuit CHS08 (BN/YE), harness side.
- DCSM (Dual Climate Controlled Seat Module) C3036C-7, circuit RHS08 (VT/WH), harness side and passenger cushion TED (Thermo-Electric Device) C3328-4, circuit RHS08 (VT/WH), harness side.
Are the resistances less than 5 ohms?
Yes
GO to AT3.
No
REPAIR the affected circuit. CLEAR the DTCs. REPEAT the self-test.
DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C327.
REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
AT3 CHECK THE RESISTANCE OF THE PASSENGER CUSHION AND BACKREST TED (Thermo-Electric Device) BLOWER MOTORS
- NOTICE: Connect the ohmmeter 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 (Thermo-Electric Device) C3328 pin 2 and pin 4, component side and between passenger backrest TED (Thermo-Electric Device) C3326 pin 2 and pin 4, component side.
Are the resistances between 4,000 ohms and 10,000 ohms?
Yes
INSTALL a new DCSM (Dual Climate Controlled Seat Module). REFER to 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.
REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
No
If the resistance of the cushion TED (Thermo-Electric Device) was not between 4,000 ohms and 10,000 ohms, INSTALL a new cushion TED (Thermo-Electric Device). REFER to Seat Cushion Thermo-Electric Device . CLEAR the DTCs. REPEAT the self-test.
If the resistance of the backrest TED (Thermo-Electric Device) was not between 4,000 ohms and 10,000 ohms, 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 passenger seat side air bag module C327.
REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.