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Circuit/System Testing

WARNING: This page is about a different car, the 2019 Buick Cascada, 2018 Buick Cascada, and 2017 Buick Cascada. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the harness connector at the appropriate seat lumbar support switch listed below, ignition ON.
    • S65D Seat Lumbar Support Switch - Driver
    • S65P Seat Lumbar Support Switch - Passenger
  2. Verify a test lamp illuminates between the B+ circuit terminal G and ground.
    • If the test lamp does not illuminate and the circuit fuse is good 
    1. Ignition OFF.
    2. Test for less than 2 Ω in the B+ circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, verify the fuse is not open and there is voltage at the fuse.
    • If the test lamp does not illuminate and the circuit fuse is open 
    1. Ignition OFF.
    2. Test for infinite resistance between the B+ circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    3. Test for greater than 10 Ω between each signal circuit listed below and ground:
      • Lumbar signal circuit terminal A
      • Lumbar signal circuit terminal B
      • Lumbar signal circuit terminal C
      • Lumbar signal circuit terminal F
      • If 10 Ω or less, disconnect the harness connector at the Q51 Seat Lumbar Support Valve Assembly and retest to verify if the short is in the circuit or the component.
      • If greater than 10 Ω, test or replace the S65 Seat Lumbar Support Switch.
    • Go to next step: If the test lamp illuminates 
  3. Ignition OFF, connect the harness connector at the S65 Seat Lumbar Support Switch and disconnect the harness connector at the Q51 Seat Lumbar Support Valve Assembly.
  4. Test for less than 10 Ω between the ground circuit terminal 5 and ground.
    • If 10 Ω or greater 
    1. Ignition OFF.
    2. Test for less than 2 Ω in the ground circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, repair the open/high resistance in the ground connection.
    • Go to next step: If less than 10 Ω 
  5. Ignition ON.
  6. Verify a test lamp turns ON and OFF between each signal circuit listed below and ground when pressing and releasing the S65 Seat Lumbar Support Switch in the appropriate direction.
    • Lumbar up switch signal terminal 1
    • Lumbar rearward switch signal terminal 2
    • Lumbar down switch signal terminal 3
    • Lumbar forward switch signal terminal 4
    • If the test lamp is always OFF 
    1. Ignition OFF, disconnect the harness connector at the S65 Seat Lumbar Support Switch.
    2. Test for infinite resistance between the signal circuit and ground.
      • If less than Infinite resistance, repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    3. Test for less than 2 Ω in the signal circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the S65 Seat Lumbar Support Switch.
    • If the test lamp is always ON 
    1. Ignition OFF, disconnect the harness connector at the S65 Seat Lumbar Support Switch, ignition ON.
    2. Test for less than 1 V between the signal circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, replace the S65 Seat Lumbar Support Switch.
    • Go to next step: If the test lamp turns ON and OFF 
  7. Ignition OFF, connect the harness connector at the Q51 Seat Lumbar Support Valve Assembly and disconnect the harness connector at the A14 Seat Lumbar Support Pump.
  8. Test for less than 10 Ω between the ground circuit terminal 3 and ground.
    • If 10 Ω or greater 
    1. Ignition OFF
    2. Test for less than 2 Ω in the ground circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, repair the open/high resistance the ground connection.
    • Go to next step: If less than 10 Ω 
  9. Connect a test lamp between the control circuit terminal 1 and ground, ignition ON.
  10. Verify the test lamp turns ON and OFF when commanding the A14 Seat Lumbar Support Pump ON and OFF by pressing and releasing the lumbar support switch in either the UP or FORWARD direction.
    • If the test lamp is always OFF 
    1. Ignition OFF, disconnect the harness connector at the Q51 Seat Lumbar Support Valve Assembly.
    2. Test for infinite resistance between the control circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    3. Test for less than 2 Ω in the control circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the Q51 Seat Lumbar Support Valve Assembly.
    • If the test lamp is always ON 
    1. Ignition OFF, disconnect the harness connector at the Q51 Seat Lumbar Support Valve Assembly, ignition ON.
    2. Test for less than 1 V between the control circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, replace the Q51 Seat Lumbar Support Valve Assembly,
    • Go to next step: If the test lamp turns ON and OFF 
  11. Test or replace the A14 Seat Lumbar Support Pump.
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