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Home › Chevrolet › 2021 › Trailblazer L › Repair and Diagnosis › Body & Frame › Body, Cab Control Systems › Vehicle Access System › Diagnostic Information and Procedures › Power Door Locks Malfunction › Circuit/System Testing

Circuit/System Testing

Test 1

    NOTE:

    It may take up to 2 min for all vehicle systems to power down before an accurate ground or low reference circuit continuity test can be performed.

  1. Ignition/Vehicle & All vehicle systems - Off
  2. Disconnect the electrical connector: S13D Door Lock Switch - Driver
  3. Test for less than 10 ohms between the test points: Ground circuit terminal 4 & Ground
    • If 10 ohms or greater 
    1. Ground Connection - Disconnect
    2. Test for less than 2 ohms between the test points: Ground circuit terminal 4 @ Component harness & Ground Connection
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Repair the open/high resistance in the ground connection.
    • Go to next step: If less than 10 ohms 
  4. Ignition - On / Vehicle - In Service Mode
  5. Verify the scan tool parameter: Driver Door Lock Switch = Inactive
    • If not the specified state 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: X6 & X7 @ K9 Body Control Module
    3. Test for infinite resistance between the test points:
      • Signal circuit terminal 2 @ Component harness & Ground
      • Signal circuit terminal 3 @ Component harness & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • If infinite resistance - Replace the component: K9 Body Control Module
    • Go to next step: If the specified state 
  6. Connect a 3 A fused jumper wire between the test points: Signal circuit terminal 2 & Ground circuit terminal 4
  7. Verify the scan tool parameter: Driver Door Lock Switch = Lock
    • If not the specified state 
    1. Ignition/Vehicle - Off & Remove - Jumper wire(s)
    2. Disconnect the electrical connector: X7 @ K9 Body Control Module
    3. Ignition - On / Vehicle - In Service Mode
    4. Test for less than 1 V between the test points: Signal circuit terminal 2 @ Component harness & Ground
      • If 1 V or greater - Repair the short to voltage on the circuit.
      • Go to next step: If less than 1 V
    5. Ignition/Vehicle - Off
    6. Test for less than 2 ohms between the test points: Signal circuit terminal 2 @ Component harness & Terminal 24 X7 @ Control module harness
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Replace the component: K9 Body Control Module
    • Go to next step: If the specified state 
  8. Connect a 3 A fused jumper wire between the test points: Signal circuit terminal 3 & Ground circuit terminal 4
  9. Verify the scan tool parameter: Driver Door Lock Switch = Unlock
    • If not the specified state 
    1. Ignition/Vehicle - Off & Remove - Jumper wire(s)
    2. Disconnect the electrical connector: X6 @ K9 Body Control Module
    3. Ignition - On / Vehicle - In Service Mode
    4. Test for less than 1 V between the test points: Signal circuit terminal 3 @ Component harness & Ground
      • If 1 V or greater - Repair the short to voltage on the circuit.
      • Go to next step: If less than 1 V
    5. Ignition/Vehicle - Off
    6. Test for less than 2 ohms between the test points: Signal circuit terminal 3 @ Component harness & Terminal 6 X6 @ Control module harness
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Replace the component: K9 Body Control Module
    • Go to next step: If the specified state 
  10. Test or replace the component: S13D Door Lock Switch - Driver

Test 2

    NOTE:

    It may take up to 2 min for all vehicle systems to power down before an accurate ground or low reference circuit continuity test can be performed.

  1. Ignition/Vehicle & All vehicle systems - Off
  2. Disconnect the electrical connector: S13P Door Lock Switch - Passenger
  3. Test for less than 10 ohms between the test points: Ground circuit terminal 4 & Ground
    • If 10 ohms or greater 
    1. Ground Connection - Disconnect
    2. Test for less than 2 ohms between the test points: Ground circuit terminal 4 @ Component harness & Ground Connection
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Repair the open/high resistance in the ground connection.
    • Go to next step: If less than 10 ohms 
  4. Ignition - On / Vehicle - In Service Mode
  5. Verify the scan tool parameter: Passenger Door Lock Switch = Inactive
    • If not the specified state 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: X7 @ K9 Body Control Module
    3. Test for infinite resistance between the test points:
      • Signal circuit terminal 2 @ Component harness & Ground
      • Signal circuit terminal 3 @ Component harness & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • If infinite resistance - Replace the component: K9 Body Control Module
    • Go to next step: If the specified state 
  6. Connect a 3 A fused jumper wire between the test points: Signal circuit terminal 2 & Ground circuit terminal 4
  7. Verify the scan tool parameter: Passenger Door Lock Switch = Lock
    • If not the specified state 
    1. Ignition/Vehicle - Off & Remove - Jumper wire(s)
    2. Disconnect the electrical connector: X7 @ K9 Body Control Module
    3. Ignition - On / Vehicle - In Service Mode
    4. Test for less than 1 V between the test points: Signal circuit terminal 2 @ Component harness & Ground
      • If 1 V or greater - Repair the short to voltage on the circuit.
      • Go to next step: If less than 1 V
    5. Ignition/Vehicle - Off
    6. Test for less than 2 ohms between the test points: Signal circuit terminal 2 @ Component harness & Terminal 12 X7 @ Control module harness
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Replace the component: K9 Body Control Module
    • Go to next step: If the specified state 
  8. Connect a 3 A fused jumper wire between the test points: Signal circuit terminal 3 & Ground circuit terminal 4
  9. Verify the scan tool parameter: Passenger Door Lock Switch = Unlock
    • If not the specified state 
    1. Ignition/Vehicle - Off & Remove - Jumper wire(s)
    2. Disconnect the electrical connector: X7 @ K9 Body Control Module
    3. Ignition - On / Vehicle - In Service Mode
    4. Test for less than 1 V between the test points: Signal circuit terminal 3 @ Component harness & Ground
      • If 1 V or greater - Repair the short to voltage on the circuit.
      • Go to next step: If less than 1 V
    5. Ignition/Vehicle - Off
    6. Test for less than 2 ohms between the test points: Signal circuit terminal 3 @ Component harness & Terminal 18 X7 @ Control module harness
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Replace the component: K9 Body Control Module
    • Go to next step: If the specified state 
  10. Test or replace the component: S13P Door Lock Switch - Passenger

Test 3

  1. Ignition/Vehicle - Off
  2. Disconnect the electrical connector: A23D Door Latch Assembly - Driver
  3. Connect a test lamp between the test points: Control circuit terminal 9 & Control circuit terminal 10
  4. Ignition - On / Vehicle - In Service Mode
  5. Operate the component: S13D Door Lock Switch - Driver - Unlock Switch & Lock Switch - Pressed

    Verify the test lamp state:

    S13D Door Lock Switch - Driver - Not Used = Test lamp Off

    Lock Switch - Pressed = Test lamp On

    Unlock Switch - Pressed = Test lamp On

    • If not the specified state 
    1. Ignition/Vehicle - Off & Remove - Test lamp
    2. Disconnect the electrical connector: K9 Body Control Module
    3. Ignition - On / Vehicle - In Service Mode
    4. Test for less than 1 V between the test points:
      • Control circuit terminal 9 @ Component harness & Ground
      • Control circuit terminal 10 @ Component harness & Ground
      • If 1 V or greater - Repair the short to voltage on the circuit.
      • Go to next step: If less than 1 V
    5. Ignition/Vehicle - Off
    6. Test for infinite resistance between the test points:
      • Control circuit terminal 9 @ Component harness & Ground
      • Control circuit terminal 10 @ Component harness & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    7. Test for less than 2 ohms between the test points:
      • Control circuit terminal 9 @ Component harness & Terminal 1 X6 @ Control module harness
      • Control circuit terminal 10 @ Component harness & Terminal 4 X6 @ Control module harness
        • If 2 ohms or greater - Repair the open/high resistance in the circuit.
        • If less than 2 ohms - Replace the component: K9 Body Control Module
    • Go to next step: If the specified state 
  6. Test or replace the component: A23D Door Latch Assembly - Driver

Test 4

  1. Ignition/Vehicle - Off
  2. Disconnect the electrical connector: A23LR Door Latch Assembly - Left Rear
  3. Connect a test lamp between the test points: Control circuit terminal 9 & Control circuit terminal 10
  4. Ignition - On / Vehicle - In Service Mode
  5. Operate the component: S13D Door Lock Switch - Driver - Unlock Switch & Lock Switch - Pressed

    Verify the test lamp state:

    S13D Door Lock Switch - Driver - Not Used = Test lamp Off

    Lock Switch - Pressed = Test lamp On

    Unlock Switch - Pressed = Test lamp On

    • If not the specified state 
    1. Ignition/Vehicle - Off & Remove - Test lamp
    2. Disconnect the electrical connector: K9 Body Control Module
    3. Ignition - On / Vehicle - In Service Mode
    4. Test for less than 1 V between the test points:
      • Control circuit terminal 9 @ Component harness & Ground
      • Control circuit terminal 10 @ Component harness & Ground
      • If 1 V or greater - Repair the short to voltage on the circuit.
      • Go to next step: If less than 1 V
    5. Ignition/Vehicle - Off
    6. Test for infinite resistance between the test points:
      • Control circuit terminal 9 @ Component harness & Ground
      • Control circuit terminal 10 @ Component harness & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    7. Test for less than 2 ohms between the test points:
      • Control circuit terminal 9 @ Component harness & Terminal 2 X6 @ Control module harness
      • Control circuit terminal 10 @ Component harness & Terminal 4 X6 @ Control module harness
        • If 2 ohms or greater - Repair the open/high resistance in the circuit.
        • If less than 2 ohms - Replace the component: K9 Body Control Module
    • Go to next step: If the specified state 
  6. Test or replace the component: A23LR Door Latch Assembly - Left Rear

Test 5

  1. Ignition/Vehicle - Off
  2. Disconnect the electrical connector: A23P Door Latch Assembly - Passenger
  3. Connect a test lamp between the test points: Control circuit terminal 7 & Control circuit terminal 8
  4. Ignition - On / Vehicle - In Service Mode
  5. Operate the component: S13D Door Lock Switch - Driver - Unlock Switch & Lock Switch - Pressed

    Verify the test lamp state:

    S13D Door Lock Switch - Driver - Not Used = Test lamp Off

    Lock Switch - Pressed = Test lamp On

    Unlock Switch - Pressed = Test lamp On

    • If not the specified state 
    1. Ignition/Vehicle - Off & Remove - Test lamp
    2. Disconnect the electrical connector: K9 Body Control Module
    3. Ignition - On / Vehicle - In Service Mode
    4. Test for less than 1 V between the test points:
      • Control circuit terminal 7 @ Component harness & Ground
      • Control circuit terminal 8 @ Component harness & Ground
      • If 1 V or greater - Repair the short to voltage on the circuit.
      • Go to next step: If less than 1 V
    5. Ignition/Vehicle - Off
    6. Test for infinite resistance between the test points:
      • Control circuit terminal 7 @ Component harness & Ground
      • Control circuit terminal 8 @ Component harness & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    7. Test for less than 2 ohms between the test points:
      • Control circuit terminal 7 @ Component harness & Terminal 2 X6 @ Control module harness
      • Control circuit terminal 8 @ Component harness & Terminal 4 X6 @ Control module harness
        • If 2 ohms or greater - Repair the open/high resistance in the circuit.
        • If less than 2 ohms - Replace the component: K9 Body Control Module
    • Go to next step: If the specified state 
  6. Test or replace the component: A23P Door Latch Assembly - Passenger

Test 6

  1. Ignition/Vehicle & All vehicle systems - Off
  2. Disconnect the electrical connector: A23RR Door Latch Assembly - Right Rear
  3. Connect a test lamp between the test points: Control circuit terminal 7 & Control circuit terminal 8
  4. Ignition - On / Vehicle - In Service Mode
  5. Operate the component: S13D Door Lock Switch - Driver - Unlock Switch & Lock Switch - Pressed

    Verify the test lamp state:

    S13D Door Lock Switch - Driver - Not Used = Test lamp Off

    Lock Switch - Pressed = Test lamp On

    Unlock Switch - Pressed = Test lamp On

    • If not the specified state 
    1. Ignition/Vehicle - Off & Remove - Test lamp
    2. Disconnect the electrical connector: K9 Body Control Module
    3. Ignition - On / Vehicle - In Service Mode
    4. Test for less than 1 V between the test points:
      • Control circuit terminal 7 @ Component harness & Ground
      • Control circuit terminal 8 @ Component harness & Ground
      • If 1 V or greater - Repair the short to voltage on the circuit.
      • Go to next step: If less than 1 V
    5. Ignition/Vehicle - Off
    6. Test for infinite resistance between the test points:
      • Control circuit terminal 7 @ Component harness & Ground
      • Control circuit terminal 8 @ Component harness & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    7. Test for less than 2 ohms between the test points:
      • Control circuit terminal 7 @ Component harness & Terminal 2 X6 @ Control module harness
      • Control circuit terminal 8 @ Component harness & Terminal 4 X6 @ Control module harness
        • If 2 ohms or greater - Repair the open/high resistance in the circuit.
        • If less than 2 ohms - Replace the component: K9 Body Control Module
    • Go to next step: If the specified state 
  6. Test or replace the component: A23RR Door Latch Assembly - Right Rear

Test 7

  1. Ignition/Vehicle - Off
  2. Disconnect the electrical connector:
    • A23D Door Latch Assembly - Driver
    • A23LR Door Latch Assembly - Left Rear
  3. Ignition - On / Vehicle - In Service Mode
  4. Verify a test lamp does not turn On between the test points:
    • A23D Door Latch Assembly - Driver Control terminal 9 & Ground
    • A23D Door Latch Assembly - Driver Control terminal 10 & Ground
    • A23LR Door Latch Assembly - Left Rear Control terminal 9 & Ground
    • If the test lamp turns On

      Repair the short to voltage on the circuit.

    • Go to next step: If the test lamp does not turn On
  5. Ignition/Vehicle - Off
  6. Disconnect the electrical connector: X6 @ K9 Body Control Module
  7. Test for infinite resistance between the test points:
    • Control circuit terminal 1 X6 @ K9 Body Control Module & Ground
    • Control circuit terminal 2 X6 @ K9 Body Control Module & Ground
    • Control circuit terminal 4 X6 @ K9 Body Control Module & Ground
    • If less than infinite resistance - Repair the short to ground on the circuit.
    • Go to next step: If infinite resistance 
  8. Verify the fuse is not open: F28DA Fuse
    • If the fuse is open 
    1. Disconnect the electrical connector: X2 @ K9 Body Control Module
    2. Test for infinite resistance between the test points: B+ circuit terminal 4 X2 & Output terminal @ Fuse
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • If less than 2 ohms - Verify the fuse is OK and there is voltage at the fuse.
    • Go to next step: If the fuse is not open
    9. NOTE:

    It may take up to 2 min for all vehicle systems to power down before an accurate ground or low reference circuit continuity test can be performed.

  9. Ignition/Vehicle & All vehicle systems - Off
  10. Test for less than 10 ohms between the test points: Ground circuit terminal 3 X6 & Ground
    • If 10 ohms or greater 
    1. Ground Connection - Disconnect
    2. Test for less than 2 ohms between the test points: Ground circuit terminal 3 X6 & Ground Connection
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Repair the open/high resistance in the ground connection.
    • Go to next step: If less than 10 ohms 
  11. Replace the component: K9 Body Control Module
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