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Pinpoint Test Aa: DTC B2729 - Driver Cushion Over-Temp Detected

WARNING: This page is about a different car, the 2006 Mercury Milan, 2006 Lincoln Zephyr, and 2006 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.
  1. AA1 CHECK THE DCSM FOR ON-DEMAND DTCS 
    WARNING: The restraint system diagnostic tool is for restraint system service only. Remove from vehicle prior to road use. Failure to remove could result in injury and possible violation of vehicle safety standards.
    NOTE: If a seat equipped with a supplemental restraint system (SRS) component is being serviced, the SRS must be depowered.  Refer to SUPPLEMENTAL RESTRAINT SYSTEM .
    NOTE: The air bag warning lamp illuminates when the RCM fuse is removed and the ignition switch is ON. This is normal operation and does not indicate a supplemental restraint system (SRS) fault.
    NOTE: The SRS must be fully operational and free of faults before releasing the vehicle to the customer.
    • Key in OFF position.
      • WARNING: Be sure that nobody is in the vehicle and that there is nothing blocking or set in front of any air bag module when the battery ground cable is connected.
    • For vehicles with seat side air bags, carry out the following:
      • Depower the SRS. Refer to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEPOWERING AND REPOWERING .
      • Disconnect the driver seat side air bag module C327.
      • Connect restraint system diagnostic tool 418-133 to driver seat side air bag module C327.
      • Disconnect the passenger seat side air bag module C313.
      • Connect restraint system diagnostic tool 418-133 to passenger seat side air bag module C313.
      • Connect the battery ground cable.
    • Enter the following diagnostic mode on the scan tool: On-Demand Self Test.
    • Was DTC B2729 retrieved during the on-demand self test? 

    Yes  : GO to AA2.

    No  : GO to  AA4.

  2. AA2 CHECK THE TED THERMISTOR CIRCUITS FOR A SHORT TO GROUND 
    • Key in OFF position.
    • Disconnect: DCSM C3305b.
    • Disconnect: Cushion TED C3300.
    • Measure the resistance between DCSM C3305b-7, circuit VHS26 (VT), harness side and ground and between DCSM C3305b-8, circuit RHS05 (YE/VT), harness side and ground.
      Fig 1: Checking TED Thermistor Circuits For Short To Ground
      G04683380Courtesy of FORD MOTOR CO.
    • Are the resistances greater than 10,000 ohms? 

    Yes  : GO to AA3.

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

    If equipped with seat side air bags, DISCONNECT the battery ground cable. DISCONNECT the restraint system diagnostic tool from driver seat side air bag module C327 and CONNECT driver seat side air bag module C327. DISCONNECT the restraint system diagnostic tool from passenger seat side air bag module C313 and CONNECT passenger seat side air bag module C313. REPOWER the SRS. REFER to SUPPLEMENTAL RESTRAINT SYSTEM .

  3. AA3 CHECK THE TED THERMISTOR 
    • Measure the resistance between cushion TED C3300 pin 5 and pin 8, component side. Note the ambient temperature and refer to the following table.
      TEMPERATURE AND RESISTANCE CHART

      Temperature Resistance
      0-10°C (32-50°F) 2782-1663 ohms
      10-20°C (50-68°F) 1837-1140 ohms
      20-30°C (68-86°F) 1260-806 ohms
      30-40°C (86-104°F) 893-570 ohms
      40-50°C (104-122°F) 630-428 ohms
      Fig 2: Checking TED Thermistor
      G04683381Courtesy of FORD MOTOR CO.
    • Is the resistance within the limits indicated? 

    Yes  : REPAIR the affected open circuit. REPEAT the self-test. CLEAR the DTCs.

    If equipped with seat side air bags, DISCONNECT the battery ground cable. DISCONNECT the restraint system diagnostic tool from driver seat side air bag module C327 and CONNECT driver seat side air bag module C327. DISCONNECT the restraint system diagnostic tool from passenger seat side air bag module C313 and CONNECT passenger seat side air bag module C313. REPOWER the SRS. REFER to SUPPLEMENTAL RESTRAINT SYSTEM .

    No  : INSTALL a new cushion TED. REPEAT the self-test. CLEAR the DTCs.

    If equipped with seat side air bags, DISCONNECT the battery ground cable. DISCONNECT the restraint system diagnostic tool from driver seat side air bag module C327 and CONNECT driver seat side air bag module C327. DISCONNECT the restraint system diagnostic tool from passenger seat side air bag module C313 and CONNECT passenger seat side air bag module C313. REPOWER the SRS. REFER to SUPPLEMENTAL RESTRAINT SYSTEM .

  4. AA4 CONFIRM THE FAULT 
    • Verify with the customer that the concern is the seat shuts OFF in HEAT mode.
      • NOTE: A crushed seat cushion foam pad or a crushed climate controlled seat manifold may be the cause of the fault. It may be necessary to sit on the seat or place something of reasonable size and weight on the seat to recreate the fault.
    • Attempt to recreate the fault. Start the vehicle and set the driver seat to HIGH HEAT for at least 15 minutes.
    • Is the customer concern with the seat hutting OFF in HEAT mode or was the fault recreated? 

    Yes  : GO to AA5.

    No  : Fault not present. Fault may have been set due to a past failure or incorrect use of the climate controlled seat system by repeated switching between HEAT and COOL modes. REPEAT the self-test. CLEAR the DTCs.

    If equipped with seat side air bags, DISCONNECT the battery ground cable. DISCONNECT the restraint system diagnostic tool from driver seat side air bag module C327 and CONNECT driver seat side air bag module C327. DISCONNECT the restraint system diagnostic tool from passenger seat side air bag module C313 and CONNECT passenger seat side air bag module C313. REPOWER the SRS. REFER to SUPPLEMENTAL RESTRAINT SYSTEM .

  5. AA5 CHECK OPERATION OF THE SEAT 
    • Key in ON position.
    • With the engine running, set both front seats to HIGH COOL (3 LEDs illuminated on EATC module).
    • Compare the airflow from the driver seat cushion and compare it to the airflow from the passenger seat cushion.
    • Is the airflow exhausting from the driver seat cushion comparable to the airflow exhausting from the passenger seat cushion? 

    Yes  : GO to  AA14.

    No  : GO to AA6.

  6. AA6 CHECK THE CUSHION BLOWER FOR AN OBSTRUCTION OR RESTRICTED FILTER 
    • Key in OFF position.
    • Inspect the blower of the cushion TED assembly for an obstruction or for a restricted filter.
    • Is the blower obstructed or the filter restricted? 

    Yes  : REMOVE the obstruction or INSTALL a new filter. REPEAT the self-test. CLEAR the DTCs.

    If equipped with seat side air bags, DISCONNECT the battery ground cable. DISCONNECT the restraint system diagnostic tool from driver seat side air bag module C327 and CONNECT driver seat side air bag module C327. DISCONNECT the restraint system diagnostic tool from passenger seat side air bag module C313 and CONNECT passenger seat side air bag module C313. REPOWER the SRS. REFER to SUPPLEMENTAL RESTRAINT SYSTEM .

    No  : GO to AA7.

  7. AA7 CHECK THE CUSHION FAN OPERATION 
    • Key in ON position.
    • With the engine running, set both front seats to HIGH COOL (3 LEDs illuminated on EATC module).
    • Inspect the cushion blower for operation.
    • Does the cushion blower operate? 

    Yes  : GO to  AA14.

    No  : GO to AA8.

  8. AA8 CHECK THE BLOWER SPEED CONTROL CIRCUIT FOR AN OPEN 
    • Key in OFF position.
    • Disconnect: DCSM C3305c.
    • Disconnect: Cushion TED C3300.
    • Measure the resistance between DCSM C3305c-11, circuit VHS18 (BN/GN), harness side and cushion TED C3300-7, circuit VHS18 (BN/GN), harness side.
      Fig 3: Checking Blower Speed Control Circuit For Open
      G04683382Courtesy of FORD MOTOR CO.
    • Is the resistance less than 5 ohms? 

    Yes  : GO to AA9.

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

    If equipped with seat side air bags, DISCONNECT the battery ground cable. DISCONNECT the restraint system diagnostic tool from driver seat side air bag module C327 and CONNECT driver seat side air bag module C327. DISCONNECT the restraint system diagnostic tool from passenger seat side air bag module C313 and CONNECT passenger seat side air bag module C313. REPOWER the SRS. REFER to SUPPLEMENTAL RESTRAINT SYSTEM .

  9. AA9 CHECK THE BLOWER- CIRCUIT FOR A SHORT TO VOLTAGE 
    • Key in ON position.
    • Measure the voltage between DCSM C3305c-15, circuit RHS03 (GY/OG), harness side and ground.
      Fig 4: Checking Blower- Circuit For Short To Voltage
      G04683383Courtesy of FORD MOTOR CO.
    • Is voltage greater than 1 volt? 

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

    If equipped with seat side air bags, DISCONNECT the battery ground cable. DISCONNECT the restraint system diagnostic tool from driver seat side air bag module C327 and CONNECT driver seat side air bag module C327. DISCONNECT the restraint system diagnostic tool from passenger seat side air bag module C313 and CONNECT passenger seat side air bag module C313. REPOWER the SRS. REFER to SUPPLEMENTAL RESTRAINT SYSTEM .

    No  : GO to AA10.

  10. AA10 CHECK THE BLOWER+ CIRCUIT FOR A SHORT TO GROUND 
    • Key in OFF position.
    • Measure the resistance between DCSM C3305c-16, circuit CHS03 (GN/BN), harness side and ground.
      Fig 5: Checking Blower+ Circuit For Short To Ground
      G04683384Courtesy of FORD MOTOR CO.
    • Is the resistance greater than 10,000 ohms? 

    Yes  : GO to AA11.

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

    If equipped with seat side air bags, DISCONNECT the battery ground cable. DISCONNECT the restraint system diagnostic tool from driver seat side air bag module C327 and CONNECT driver seat side air bag module C327. DISCONNECT the restraint system diagnostic tool from passenger seat side air bag module C313 and CONNECT passenger seat side air bag module C313. REPOWER the SRS. REFER to SUPPLEMENTAL RESTRAINT SYSTEM .

  11. AA11 CHECK THE BLOWER+ AND BLOWER- CIRCUITS FOR AN OPEN 
    • Measure the resistance between DCSM C3305C-16, circuit CHS03 (GN/BN), harness side and cushion TED C3300-2, circuit CHS03 (GN/BN), harness side; and between DCSM C3305C-1., circuit RHS03 (GY/OG), harness side and cushion TED C3300-4, circuit RHS03 (GY/OG), harness side.
      Fig 6: Checking Blower+ And Blower- Circuits For Open
      G04683385Courtesy of FORD MOTOR CO.
    • Are the resistances less than 5 ohms? 

    Yes  : GO to AA12.

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

    If equipped with seat side air bags, DISCONNECT the battery ground cable. DISCONNECT the restraint system diagnostic tool from driver seat side air bag module C327 and CONNECT driver seat side air bag module C327. DISCONNECT the restraint system diagnostic tool from passenger seat side air bag module C313 and CONNECT passenger seat side air bag module C313. REPOWER the SRS. REFER to SUPPLEMENTAL RESTRAINT SYSTEM .

  12. AA12 CHECK THE BLOWER+ TO BLOWER- RESISTANCE 
      CAUTION: 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.
      Fig 7: Checking Blower+ To Blower- Resistance
      G04683386Courtesy of FORD MOTOR CO.
    • Measure the resistance between cushion TED C3300 pin 2 and pin 4, component side.
    • Is the resistance between 6 Kohms and 9 Kohms? 

    Yes  : GO to AA13.

    No  : INSTALL a new cushion TED. REPEAT the self-test. CLEAR the DTCs.

    If equipped with seat side air bags, DISCONNECT the battery ground cable. DISCONNECT the restraint system diagnostic tool from driver seat side air bag module C327 and CONNECT driver seat side air bag module C327. DISCONNECT the restraint system diagnostic tool from passenger seat side air bag module C313 and CONNECT passenger seat side air bag module C313. REPOWER the SRS. REFER to SUPPLEMENTAL RESTRAINT SYSTEM .

  13. AA13 CHECK THE BLOWER SPEED CONTROL RESISTANCE 
      CAUTION: 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.
      Fig 8: Checking Blower Speed Control Resistance
      G04683387Courtesy of FORD MOTOR CO.
    • Measure the resistance between cushion TED C3300 pin 7 and pin 4, component side.
    • Is the resistance between 290 Kohms and 420 Kohms? 

    Yes  : GO to AA14.

    No  : INSTALL a new cushion TED. REPEAT the self-test. CLEAR the DTCs.

    If equipped with seat side air bags, DISCONNECT the battery ground cable. DISCONNECT the restraint system diagnostic tool from driver seat side air bag module C327 and CONNECT driver seat side air bag module C327. DISCONNECT the restraint system diagnostic tool from passenger seat side air bag module C313 and CONNECT passenger seat side air bag module C313. REPOWER the SRS. REFER to SUPPLEMENTAL RESTRAINT SYSTEM .

  14. AA14 CHECK THE TED INSTALLATION AND FOR CRUSHED SEAT CUSHION 
    • Remove the seat. Refer to SEAT - FRONT .
    • Remove the seat cushion trim cover. Refer to SEAT CUSHION COVER - FRONT .
    • Inspect the seat cushion for the following:
      • Is the TED correctly installed?
      • Is the seat cushion 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  : INSTALL a new DCSM and CARRY OUT programmable module installation (PMI). REFER to CLIMATE CONTROLLED SEAT MODULE . REPEAT the self-test. CLEAR the DTCs.

    If equipped with seat side air bags, DISCONNECT the battery ground cable. DISCONNECT the restraint system diagnostic tool from driver seat side air bag module C327 and CONNECT driver seat side air bag module C327. DISCONNECT the restraint system diagnostic tool from passenger seat side air bag module C313 and CONNECT passenger seat side air bag module C313. REPOWER the SRS. REFER to SUPPLEMENTAL RESTRAINT SYSTEM .

    No  : CORRECTLY install the cushion TED or INSTALL a new seat cushion foam pad and/or climate controlled seat manifold. REPEAT the self-test. CLEAR the DTCs.

    If equipped with seat side air bags, DISCONNECT the battery ground cable. DISCONNECT the restraint system diagnostic tool from driver seat side air bag module C327 and CONNECT driver seat side air bag module C327. DISCONNECT the restraint system diagnostic tool from passenger seat side air bag module C313 and CONNECT passenger seat side air bag module C313. REPOWER the SRS. REFER to SUPPLEMENTAL RESTRAINT SYSTEM .

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