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Home >> Cadillac >> 2021 >> CT4 Sport, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 377 (Power Seats) >> Diagnostic Information and Procedures >> Lumbar/Bolster/Massage Malfunction (4-Way With AHE, AHH, AF6, or AKE) >> 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.

Seat Lumbar Switch Circuit Test 

  1. Ignition/Vehicle OFF, disconnect the connector at the appropriate front seat lumbar switch listed below. It may take up to 2 min for all vehicle systems to power down.
    • S65D Front Seat Lumbar Switch - Driver
    • S65P Front Seat Lumbar Switch - Passenger
  2. Test for less than 10 Ω between the low reference circuit terminal 4 and ground.
    • If 10 Ω or greater 
    1. Test the appropriate low reference circuit listed below for an open/high resistance:
      • S65D Front Seat Lumbar Switch - Driver = Circuit 2817
      • S65P Front Seat Lumbar Switch - Passenger = Circuit 2815
      • 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 appropriate S64 Front Seat Adjuster Switch.
    • Go to next step: If less than 10 Ω 
  3. Ignition/Vehicle in Service Mode.
  4. Test for 4.8 - 5.2 V between the signal circuit terminal 3 and ground.
    • If less than 4.8 V 
    1. Test the appropriate circuit for a short to ground:
      • S65D Front Seat Lumbar Switch - Driver = Circuit 2818
      • S65P Front Seat Lumbar Switch - Passenger = Circuit 2816
      • 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:
      • S65D Front Seat Lumbar Switch - Driver = Circuit 2818
      • S65P Front Seat Lumbar Switch - Passenger = Circuit 2816
      • 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 appropriate S64 Front Seat Adjuster Switch.
    • If greater than 5.2 V 
    1. Test the appropriate circuit for a short to voltage:
      • S65D Front Seat Lumbar Switch - Driver = Circuit 2818
      • S65P Front Seat Lumbar Switch - Passenger = Circuit 2816
      • 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 appropriate S64 Front Seat Adjuster Switch.
    • Go to next step: If between 4.8 - 5.2 V 
  5. Ignition/Vehicle OFF, connect the connector at the S65 Front Seat Lumbar Switch and disconnect the connector at the appropriate S64 Front Seat Adjuster Switch.
  6. Connect a DMM between the signal circuit terminal 5 and the low reference circuit terminal 6.
  7. Test for the resistance values listed below while pressing the appropriate S65 Front Seat Lumbar Switch.
    • 450 - 500 Ω for Switch 1
    • 1012 - 1118 Ω for Switch 2
    • 1854 - 2050 Ω for Switch 3
    • 3280 - 3625 Ω for Switch 4
    • 6072 - 6712 Ω for Switch 5
    • If not between the specified values 

      Test or replace the appropriate S65 Front Seat Lumbar Switch.

    • Go to next step: If between the specified values 
  8. Test or replace the S64 Front Seat Adjuster Switch.

Seat Lumbar Circuit Test 

  1. Ignition/Vehicle OFF, disconnect the connector at the appropriate front seat bolster memory module listed below. It may take up to 2 min for all vehicle systems to power down.
    • K134D Front Seat Bolster Memory Module - Driver
    • K134P Front Seat Bolster Memory Module - Passenger
  2. Test for less than 10 Ω between the ground circuit terminal 4 and ground.
    • If 10 Ω or greater 
    1. Test the appropriate circuit for an open/high resistance:
      • K134D Front Seat Bolster Memory Module - Driver = Circuit 2150
      • K134P Front Seat Bolster Memory Module - Passenger = Circuit 2250
      • 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. Repair the open/high resistance in the ground connection.
    • Go to next step: If less than 10 Ω 
  3. Ignition/Vehicle in Service Mode.
  4. Verify a test lamp illuminates between the B+ circuit terminal 1 and ground.
    • If the test lamp does not illuminate 
    1. Test the appropriate circuit for a short to ground:
      • K134D Front Seat Bolster Memory Module - Driver = Circuit 2040
      • K134P Front Seat Bolster Memory Module - Passenger = Circuit 740
      • 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:
      • K134D Front Seat Bolster Memory Module - Driver = Circuit 2040
      • K134P Front Seat Bolster Memory Module - Passenger = Circuit 740
      • 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. Verify the fuse is OK and there is voltage at the fuse.
    • Go to next step: If the test lamp illuminates 
  5. Ignition/Vehicle OFF, connect the connector at the K134 Front Seat Bolster Memory Module and disconnect the connector at the appropriate front seat back lumbar pump listed below:
    • G31D Front Seat Back Lumbar Pump - Driver
    • G31P Front Seat Back Lumbar Pump - Passenger
  6. Connect a test lamp between the control circuit terminal 1 and ground circuit terminal 2.
  7. Ignition/Vehicle in Service Mode.
  8. Verify the test lamp turns ON when pressing the lumbar forward switch.
    • If the test lamp remains OFF 
    1. Test the appropriate circuits for a short to ground:
      • G31D Front Seat Back Lumbar Pump - Driver = Circuit 2305 and circuit 4891
      • G31P Front Seat Back Lumbar Pump - Passenger = Circuit 2306 and circuit 4890
      • 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 circuits for an open/high resistance:
      • G31D Front Seat Back Lumbar Pump - Driver = Circuit 2305 and circuit 4891
      • G31P Front Seat Back Lumbar Pump - Passenger = Circuit 2306 and circuit 4890
      • 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 appropriate K134 Front Seat Bolster Memory Module.
    • If the test lamp remains ON 
    1. Test the appropriate circuits for a short to voltage:
      • G31D Front Seat Back Lumbar Pump - Driver = Circuit 2305 and circuit 4891
      • G31P Front Seat Back Lumbar Pump - Passenger = Circuit 2306 and circuit 4890
      • 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 appropriate K134 Front Seat Bolster Memory Module.
    • Go to next step: If the test lamp turns ON and OFF 
  9. Test or replace the appropriate G31 Seat Lumbar/Bolster Pump.
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