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Home >> Cadillac >> 2021 >> CT4 Sport, RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 376 (Seat Heating System And Seat Cooling System) >> Diagnostic Information and Procedures >> Front Heated Seat Malfunction >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2022 Cadillac CT5. However, it is still accessible from the selected car via links, so may be relevant.

Both Heated Seats are Inoperative

    NOTE:

    Circuit/System Verification must be performed before proceeding with Circuit/System Testing.

  1. Ignition OFF, disconnect the X1 connector at the K29F Front Seat Heater Control Module, ignition ON.
  2. Verify a test lamp illuminates between the B+ circuit terminal 10 and ground.
    • If the test lamp does not illuminate and the circuit fuse is good 
    1. Repair the open/high resistance on circuit 6640.
    • If the test lamp does not illuminate and the circuit fuse is open 
    1. Test circuit 6640 for a short to ground.
      • If a short to ground is found, repair the fault on the circuit.
      • Go to next step: If a short to ground is not found
    2. Replace the K29F Front Seat Heater Control Module.
    • Go to next step: If the test lamp illuminates 
  3. Verify a test lamp illuminates between the B+ circuit terminal 7 and ground.
    • If the test lamp does not illuminate and the circuit fuse is good 
    1. Repair the open/high resistance on circuit 6140.
    • If the test lamp does not illuminate and the circuit fuse is open 
    1. Test circuit 6140 for a short to ground.
      • If a short to ground is found, repair the fault on the circuit.
      • Go to next step: If a short to ground is not found
    2. Replace the K29F Front Seat Heater Control Module.
    • Go to next step: If the test lamp illuminates 
  4. Test for less than 1 V between control circuit terminal 2 and ground.
    • If 1 V or greater 
    1. Repair the short to voltage on circuit 2479, circuit 2480, or circuit 2481.
    • Go to next step: If less than 1 V 
  5. Test for less than 1 V between control circuit terminal 6 and ground.
    • If 1 V or greater 
    1. Repair the short to voltage on circuit 2077, circuit 2078, or circuit 2432.
    • Go to next step: If less than 1 V 
  6. Ignition OFF.
  7. Test for infinite resistance between control circuit terminal 2 and ground.
    • If less than infinite resistance 
    1. Repair the short to ground on circuit 2479, circuit 2480, or circuit 2481.
    • Go to next step: If infinite resistance 
  8. Test for infinite resistance between control circuit terminal 6 and ground.
    • If less than infinite resistance 
    1. Repair the short to ground on circuit 2077, circuit 2078, or circuit 2432.
    • Go to next step: If infinite resistance 
  9. Replace the K29F Front Seat Heater Control Module.

One Heated Seat is Inoperative

    NOTE:

    Circuit/System Verification must be performed before proceeding with Circuit/System Testing

  1. Ignition OFF, disconnect the X1 connector at the K29F Front Seat Heater Control Module, ignition ON.
  2. Verify a test lamp illuminates between the B+ circuit terminal 7 and ground.
    • If the test lamp does not illuminate and the circuit fuse is good 
    1. Repair the open/high resistance on the circuit 6140.
    • If the test lamp does not illuminate and the circuit fuse is open 
    1. Test the circuit 6140 for a short to ground.
      • If a short to ground is found, repair the fault on the circuit.
      • Go to next step: If a short to ground is not found
    2. Replace the K29F Front Seat Heater Control Module.
    • Go to next step: If the test lamp illuminates 
  3. Ignition OFF, connect the X1 connector at the K29F Front Seat Heater Control Module. Disconnect the connector at the appropriate components:
    • Driver heated seat inoperative = E14A Front Seat Back Heater - Driver and the E14B Front Seat Cushion Heater - Driver
    • Passenger heated seat inoperative = E14C Front Seat Back Heater - Passenger and the E14D Front Seat Cushion Heater - Passenger
  4. Ignition ON.
    5. NOTE:

    When performing this test ensure that you are testing from the correct terminal. Testing from the incorrect terminal will cause a misdiagnosis of the circuit. Three of the four terminals in this connector will not only display a voltage reading but a different voltage reading.

  5. Test for 4.8 - 5.2 V between the appropriate signal circuit terminal and ground:
    • E14B Front Seat Cushion Heater - Driver = Terminal 2
    • E14D Front Seat Cushion Heater - Passenger = Terminal 2
    • If less than 4.8 V 
    1. Test the appropriate circuit for a short to ground:
      • E14B Front Seat Cushion Heater - Driver = Circuit 2079
      • E14D Front Seat Cushion Heater - Passenger = Circuit 2434
      • If a short to ground is found, repair the fault on the circuit.
      • Go to next step: If a short to ground is not found
    2. Test the appropriate circuit for an open/high resistance:
      • E14B Front Seat Cushion Heater - Driver = Circuit 2079
      • E14D Front Seat Cushion Heater - Passenger = Circuit 2434
      • If an open/high resistance is found, repair the fault on the circuit.
      • Go to next step: If an open/high resistance is not found
    3. Replace the K29F Front Seat Heater Control Module.
    • If greater than 5.2 V 
    1. Test the appropriate circuit for a short to voltage:
      • E14B Front Seat Cushion Heater - Driver = Circuit 2079
      • E14D Front Seat Cushion Heater - Passenger = Circuit 2434
      • If a short to voltage is found, repair the fault on the circuit.
      • Go to next step: If a short to voltage is not found
    2. Replace the K29F Front Seat Heater Control Module.
    • Go to next step: If between 4.8 - 5.2 V 
    6. NOTE:

    When performing this test ensure that you are testing from the correct terminal. Testing from the incorrect terminal will cause a misdiagnosis of the circuit. Three of the four terminals in this connector will not only display a voltage reading but a different voltage reading.

  6. Test for 4.8 - 5.2 V between the appropriate signal circuit terminal and ground:
    • E14A Front Seat Back Heater - Driver = Terminal 2
    • E14C Front Seat Back Heater - Passenger = Terminal 2
    • If less than 4.8 V 
    1. Test the appropriate circuit for a short to ground:
      • E14A Front Seat Back Heater - Driver = Circuit 2425
      • E14C Front Seat Back Heater - Passenger = Circuit 2436
      • If a short to ground is found, repair the fault on the circuit.
      • Go to next step: If a short to ground is not found
    2. Test the appropriate circuit for an open/high resistance:
      • E14A Front Seat Back Heater - Driver = Circuit 2425
      • E14C Front Seat Back Heater - Passenger = Circuit 2436
      • If an open/high resistance is found, repair the fault on the circuit.
      • Go to next step: If an open/high resistance is not found
    3. Replace the K29F Front Seat Heater Control Module.
    • If greater than 5.2 V 
    1. Test the appropriate circuit for a short to voltage:
      • E14A Front Seat Back Heater - Driver = Circuit 2425
      • E14C Front Seat Back Heater - Passenger = Circuit 2436
      • If a short to voltage is found, repair the fault on the circuit.
      • Go to next step: If a short to voltage is not found
    2. Replace the K29F Front Seat Heater Control Module.
    • Go to next step: If between 4.8 - 5.2 V 
  7. Connect a test lamp between the appropriate control circuit terminals:
    • E14A Front Seat Back Heater - Driver = Terminal 1 and terminal 4
    • E14C Front Seat Back Heater - Passenger = Terminal 1 and terminal 4
  8. Engine running.
    9. NOTE:

    The test lamp should turn ON for approximately 10 s after the heated seat is commanded ON.

  9. Verify the test lamp turns ON after pressing the appropriate heated seat switch.
    • If the test lamp is always OFF 
    1. Test the appropriate circuits for an open/high resistance:
      • E14A Front Seat Back Heater - Driver = Circuit 2432 and circuit 2078
      • E14C Front Seat Back Heater - Passenger = Circuit 2481 and circuit 2480
      • If an open/high resistance is found, repair the fault on the circuit.
      • Go to next step: If an open/high resistance is not found
    2. Replace the K29F Front Seat Heater Control Module.
    • Go to next step: If the test lamp turns ON 
  10. Connect the connector at the appropriate component:
    • E14B Front Seat Cushion Heater - Driver
    • E14D Front Seat Cushion Heater - Passenger
  11. Verify the test lamp turns ON after pressing the appropriate heated seat switch.
    • If the test lamp is always OFF 
      NOTE:

      Because of the type of material used in the heater element, a reliable resistance value is unavailable for a component test.

    1. Replace the appropriate component:
      • E14B Front Seat Cushion Heater - Driver
      • E14D Front Seat Cushion Heater - Passenger
    • Go to next step: If the test lamp turns ON 
    12. NOTE:

    Because of the type of material used in the heater element, a reliable resistance value is unavailable for a component test.

  12. Replace the appropriate component:
    • E14A Front Seat Back Heater - Driver
    • E14C Front Seat Back Heater - Passenger

One Heating Element is Inoperative

    NOTE:

    Circuit/System Verification must be performed before proceeding with Circuit/System Testing.

  1. Ignition OFF, disconnect the connector at the appropriate E14 Front Seat Heater.
  2. Connect a test lamp between control circuit terminal 1 and control circuit terminal 4, engine ON.
    3. NOTE:

    The test lamp should turn ON for approximately 10 s after the heated seat is commanded ON.

  3. Verify the test lamp turns ON after pressing the heated seat switch.
    • If the test lamp is always OFF 
    1. Test the appropriate circuits for an open/high resistance:
      • E14A Front Seat Back Heater - Driver = Circuit 2432 and Circuit 2078
      • E14B Front Seat Cushion Heater - Driver = Circuit 2077 and Circuit 2078
      • E14C Front Seat Back Heater - Passenger = Circuit 2479 and Circuit 2480
      • E14D Front Seat Cushion Heater - Passenger = Circuit 2481 and Circuit 2480
    • Go to next step: If the test lamp turns ON 
    4. NOTE:

    Because of the type of material used in the heater element, a reliable resistance value is unavailable for a component test.

  4. Replace the appropriate E14 Front Seat Heater.

Degraded Heated Seat Operation Driver Seat

    NOTE:

    Circuit/System Verification must be performed before proceeding with Circuit/System Testing

  1. Ignition OFF, disconnect the connector at each component listed below. It may take up to 2 min for all vehicle systems to power down.
    • E14A Front Seat Back Heater - Driver
    • E14B Front Seat Cushion Heater - Driver
  2. Test for less than 40 Ω between each low reference circuit terminal listed below and ground, one at a time.
    • E14A Front Seat Back Heater - Driver = Terminal 3
    • E14B Front Seat Cushion Heater - Driver = Terminal 3
    • If 40 Ω or greater 
    1. Test circuit 2080 for an open/high resistance.
      • If an open/high resistance is found, repair the fault on the circuit.
      • Go to next step: If an open/high resistance is not found
    2. Replace the K29F Front Seat Heater Control Module.
    • Go to next step: If less than 40 Ω 
  3. Ignition ON.
  4. Test for 4.8 - 5.2 V between each signal circuit terminal listed below and ground, one at a time.
    • E14A Front Seat Back Heater - Driver = Terminal 2
    • E14B Front Seat Cushion Heater - Driver = Terminal 2
    • If less than 4.8 V 
    1. Test the appropriate circuit for a short to ground:
      • E14A Front Seat Back Heater - Driver = Circuit 2425
      • E14B Front Seat Cushion Heater - Driver = Circuit 2079
      • If a short to ground is found, repair the fault on the circuit.
      • Go to next step: If a short to ground is not found
    2. Test the appropriate circuit for an open/high resistance:
      • E14A Front Seat Back Heater - Driver = Circuit 2425
      • E14B Front Seat Cushion Heater - Driver = Circuit 2079
      • If an open/high resistance is found, repair the fault on the circuit.
      • Go to next step: If an open/high resistance is not found
    3. Replace the K29F Front Seat Heater Control Module.
    • If greater than 5.2 V 
    1. Test the appropriate circuit for a short to voltage:
      • E14A Front Seat Back Heater - Driver = Circuit 2425
      • E14B Front Seat Cushion Heater - Driver = Circuit 2079
      • If a short to voltage is found, repair the fault on the circuit.
      • Go to next step: If a short to voltage is not found
    2. Replace the K29F Front Seat Heater Control Module.
    • Go to next step: If between 4.8 - 5.2 V 
  5. Ignition OFF, connect the connector at the E14B Front Seat Cushion Heater - Driver and the E14A Front Seat Back Heater - Driver. Disconnect the X2 connector at the K29F Front Seat Heater Control Module.
  6. Test for 500 Ω - 300 kΩ between the signal circuit and the low reference circuit terminals listed below, one at a time.
    • Terminal 3 and terminal 1 at K29F Front Seat Heater Control Module
    • Terminal 6 and terminal 1 at K29F Front Seat Heater Control Module
    • If not between 500 Ω - 300 kΩ 
    1. Replace the appropriate component:
      • Terminal 3 and terminal 1 at K29F Front Seat Heater Control Module = E14A Front Seat Back Heater - Driver
      • Terminal 6 and terminal 1 at K29F Front Seat Heater Control Module = E14B Front Seat Cushion Heater - Driver
    • Go to next step: If between 500 Ω - 300 kΩ 
  7. Replace the K29F Front Seat Heater Control Module.

Degraded Heated Seat Operation Passenger Seat

    NOTE:

    Circuit/System Verification must be performed before proceeding with Circuit/System Testing

  1. Ignition OFF, disconnect the connector at each component listed below. It may take up to 2 min for all vehicle systems to power down.
    • E14C Front Seat Back Heater - Passenger
    • E14D Front Seat Cushion Heater - Passenger
  2. Test for less than 40 Ω between each low reference circuit terminal listed below and ground, one at a time.
    • E14C Front Seat Back Heater - Passenger = Terminal 3
    • E14D Front Seat Cushion Heater - Passenger = Terminal 3
    • If 40 Ω or greater 
    1. Test the appropriate circuit for an open/high resistance:
      • E14C Front Seat Back Heater - Passenger = Circuit 2482
      • E14D Front Seat Cushion Heater - Passenger = Circuit 2435
      • If an open/high resistance is found, repair the fault on the circuit.
      • Go to next step: If an open/high resistance is not found
    2. Replace the K29F Front Seat Heater Control Module.
    • Go to next step: If less than 40 Ω 
  3. Ignition ON.
  4. Test for 4.8 - 5.2 V between each signal circuit terminal listed below and ground, one at a time.
    • E14C Front Seat Back Heater - Passenger = Terminal 2
    • E14D Front Seat Cushion Heater - Passenger = Terminal 2
    • If less than 4.8 V 
    1. Test the appropriate circuit for a short to ground:
      • E14C Front Seat Back Heater - Passenger = Circuit 2436
      • E14D Front Seat Cushion Heater - Passenger = Circuit 2434
      • If a short to ground is found, repair the fault on the circuit.
      • Go to next step: If a short to ground is not found
    2. Test the appropriate circuit for an open/high resistance:
      • E14C Front Seat Back Heater - Passenger = Circuit 2436
      • E14D Front Seat Cushion Heater - Passenger = Circuit 2434
      • If an open/high resistance is found, repair the fault on the circuit.
      • Go to next step: If an open/high resistance is not found
    3. Replace the K29F Front Seat Heater Control Module.
    • If greater than 5.2 V 
    1. Test the appropriate circuit for a short to voltage:
      • E14C Front Seat Back Heater - Passenger = Circuit 2436
      • E14D Front Seat Cushion Heater - Passenger = Circuit 2434
      • If a short to voltage is found, repair the fault on the circuit.
      • Go to next step: If a short to voltage is not found
    2. Replace the K29F Front Seat Heater Control Module.
    • Go to next step: If between 4.8 - 5.2 V 
  5. Ignition OFF, connect the connector at the E14D Front Seat Cushion Heater - Passenger and the E14C Front Seat Back Heater - Passenger. Disconnect the X2 connector at the K29F Front Seat Heater Control Module.
  6. Test for 500 Ω - 300 kΩ between the signal circuit and the low reference circuit terminals listed below, one at a time.
    • Terminal 4 and terminal 12 at K29F Front Seat Heater Control Module
    • Terminal 5 and terminal 2 at K29F Front Seat Heater Control Module
    • If not between 500 Ω - 300 kΩ 
    1. Replace the appropriate component:
      • Terminal 4 and terminal 12 at K29F Front Seat Heater Control Module = E14C Front Seat Back Heater - Passenger
      • Terminal 5 and terminal 2 at K29F Front Seat Heater Control Module = E14D Front Seat Cushion Heater - Passenger
    • Go to next step: If between 500 Ω - 300 kΩ 
  7. Replace the K29F Front Seat Heater Control Module.
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