LEMON Manuals: Even more car manuals for everyone
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 >> Vented 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.
  1. Ignition OFF and all vehicle systems OFF, disconnect the appropriate two seat blower motors listed below:
    • M73A Front Seat Back Ventilation Blower - Driver and M73D Front Seat Cushion Ventilation Blower - Driver
    • M73B Front Seat Back Ventilation Blower - Passenger and M73P Front Seat Cushion Ventilation Blower - Passenger
  2. Verify a test lamp illuminates between the appropriate ground circuit terminals listed below and B+, one at a time.
    • Terminal 3 at M73A Front Seat Back Ventilation Blower - Driver
    • Terminal 3 at M73D Front Seat Cushion Ventilation Blower - Driver
    • Terminal 3 at M73B Front Seat Back Ventilation Blower - Passenger
    • Terminal 3 at M73P Front Seat Cushion Ventilation Blower - Passenger
    • If the test lamp does not illuminate 
    1. Test the appropriate circuit for an open/high resistance:
      • Terminal 3 at M73A Front Seat Back Ventilation Blower - Driver = Circuit 1150
      • Terminal 3 at M73D Front Seat Cushion Ventilation Blower - Driver = Circuit 1150
      • Terminal 3 at M73B Front Seat Back Ventilation Blower - Passenger = Circuit 1250
      • Terminal 3 at M73P Front Seat Cushion Ventilation Blower - Passenger = Circuit 1250
    2. Repair the open/high resistance in the ground connection.
    • Go to next step: If the test lamp illuminates 
  3. Verify a test lamp illuminates between the appropriate B+ circuit terminals listed below and ground, one at a time.
    • Terminal 1 at M73A Front Seat Back Ventilation Blower - Driver
    • Terminal 1 at M73D Front Seat Cushion Ventilation Blower - Driver
    • Terminal 1 at M73B Front Seat Back Ventilation Blower - Passenger
    • Terminal 1 at M73P Front Seat Cushion Ventilation Blower - Passenger
    • If the test lamp does not illuminate and the circuit fuse is good 

      Repair the open/high resistance on the circuit 539.

    • If the test lamp does not illuminate and the circuit fuse is open 
    1. Test the circuit 539 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 appropriate M73 Seat Blower Motor.
  4. Connect a test lamp between the appropriate control circuit terminal and B+, one at a time.
    • Terminal 2 at M73A Front Seat Back Ventilation Blower - Driver
    • Terminal 2 at M73D Front Seat Cushion Ventilation Blower - Driver
    • Terminal 2 at M73B Front Seat Back Ventilation Blower - Passenger
    • Terminal 2 at M73P Front Seat Cushion Ventilation Blower - Passenger
  5. Ignition ON, Verify the test lamp turns ON when pressing the vented seat switch through the High, Medium, and Low positions and the test lamp turns OFF when the OFF position is reached.
    • If the test lamp does not turn ON 
    1. Test the appropriate circuit for a short to voltage:
      • Terminal 2 at M73A Front Seat Back Ventilation Blower - Driver = Circuit 5906
      • Terminal 2 at M73D Front Seat Cushion Ventilation Blower - Driver = Circuit 5906
      • Terminal 2 at M73B Front Seat Back Ventilation Blower - Passenger = Circuit 5908
      • Terminal 2 at M73P Front Seat Cushion Ventilation Blower - Passenger = Circuit 5908
      • 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. Test the appropriate circuit for an open/high resistance:
      • Terminal 2 at M73A Front Seat Back Ventilation Blower - Driver = Circuit 5906
      • Terminal 2 at M73D Front Seat Cushion Ventilation Blower - Driver = Circuit 5906
      • Terminal 2 at M73B Front Seat Back Ventilation Blower - Passenger = Circuit 5908
      • Terminal 2 at M73P Front Seat Cushion Ventilation Blower - Passenger = Circuit 5908
      • 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 the test lamp does not turn OFF 
    1. Test the appropriate circuit for a short to ground:
      • Terminal 2 at M73A Front Seat Back Ventilation Blower - Driver = Circuit 5906
      • Terminal 2 at M73D Front Seat Cushion Ventilation Blower - Driver = Circuit 5906
      • Terminal 2 at M73B Front Seat Back Ventilation Blower - Passenger = Circuit 5908
      • Terminal 2 at M73P Front Seat Cushion Ventilation Blower - Passenger = Circuit 5908
      • 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 turns ON and OFF 
  6. Replace the appropriate malfunctioning seat blower motor.
    • M73A Front Seat Back Ventilation Blower - Driver
    • M73D Front Seat Cushion Ventilation Blower - Driver
    • M73B Front Seat Back Ventilation Blower - Passenger
    • M73P Front Seat Cushion Ventilation Blower - Passenger
scientia non olet · About LEMON Manuals