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July 1: So it begins. Don't worry, this is not in the correct legal jurisdiction!

Circuit/System Testing

WARNING: This page is about a different car, the 2020 Buick Regal TourX, 2020 Buick Regal, 2019 Buick Regal TourX, and 2019 Buick Regal. However, it is still accessible from the selected car via links, so may be relevant.

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: S146 Window/Outside Rearview Mirror Switch - Driver
  3. Test for less than 10 ohms between the test points: Ground circuit terminal 24 & Ground
    • If 10 ohms or greater 
    1. Ground Connection - Disconnect
    2. Test for less than 2 ohms between the test points: Ground circuit terminal 24 @ 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 a test lamp turns On between the test points: B+ circuit terminal 23 & Ground
    • If the test lamp does not turn On and the circuit fuse is OK 
    1. Ignition/Vehicle - Off & Remove - Test lamp
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Verify the fuse is OK and there is voltage at the fuse.
    • If the test lamp does not turn On and the circuit fuse is open 
    1. Ignition/Vehicle - Off & Remove - Test lamp
    2. Test for infinite resistance between the test points: B+ circuit terminal 23 & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • If infinite resistance - Replace the component: S146 Window/Outside Rearview Mirror Switch - Driver
    • Go to next step: If the test lamp turns On 
  6. Verify the scan tool parameter: Driver Window Main Control Down Switch = Inactive
    • If not the specified state 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: M74D Window Motor - Driver
    3. Test for infinite resistance between the test points: Signal circuit terminal 1 @ Component harness & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • If infinite resistance - Replace the component: M74D Window Motor - Driver
    • Go to next step: If the specified state 
  7. Momentarily connect a 3 A fused jumper wire between the test points: Signal circuit terminal 1 & Ground circuit terminal 24

    Verify the scan tool parameter: Driver Window Main Control Down Switch = Active

    • If not the specified state 
    1. Ignition/Vehicle - Off & Remove - Jumper wire(s)
    2. Disconnect the electrical connector: M74D Window Motor - Driver
    3. Ignition - On/Vehicle - In Service Mode
    4. Test for less than 1 V between the test points: Signal circuit terminal 1 @ 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 1 @ Component harness & Signal circuit terminal 7 @ M74D Window Motor - Driver
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Replace the component: M74D Window Motor - Driver
    • Go to next step: If the specified state 
  8. Verify the scan tool parameter: Driver Window Main Control Up Switch = Inactive
    • If not the specified state 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: M74D Window Motor - Driver
    3. Test for infinite resistance between the test points: Signal circuit terminal 11 @ Component harness & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • If infinite resistance - Replace the component: M74D Window Motor - Driver
    • Go to next step: If the specified state 
  9. Momentarily connect a 3 A fused jumper wire between the test points: Signal circuit terminal 11 & Ground circuit terminal 24

    Verify the scan tool parameter: Driver Window Main Control Up Switch = Active

    • If not the specified state 
    1. Ignition/Vehicle - Off & Remove - Jumper wire(s)
    2. Disconnect the electrical connector: M74D Window Motor - Driver
    3. Ignition - On/Vehicle - In Service Mode
    4. Test for less than 1 V between the test points: Signal circuit terminal 11 @ 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 11 @ Component harness & Signal circuit terminal 3 @ M74D Window Motor - Driver
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Replace the component: M74D Window Motor - Driver
    • Go to next step: If the specified state 
  10. Test for greater than 10 V between the test points: Signal circuit terminal 5 @ Component harness & Ground
    • If 10 V or less 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: M74D Window Motor - Driver
    3. Test for infinite resistance between the test points: Signal circuit terminal 5 @ Component harness & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • Go to next step: If less than infinite resistance
    4. Test for less than 2 ohms between the test points: Signal circuit terminal 5 @ Component harness & Signal circuit terminal 5 @ M74D Window Motor - Driver
    • If 2 ohms or greater - Repair the open/high resistance in the circuit.
    • If less than 2 ohms - Replace the component: M74D Window Motor - Driver
    • Go to next step: If greater than 10 V 
  11. Test or replace the component: S146 Window/Outside Rearview Mirror 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: S79P Window Switch - Passenger
  3. Test for less than 10 ohms between the test points:
    • {Without A45} or {Without A44} Ground circuit terminal 1 & Ground
    • {With A45} or {With A44} Ground circuit terminal 24 & Ground
    • If 10 ohms or greater 
    1. Ground Connection - Disconnect
    2. Test for less than 2 ohms between the test points:
      • {Without A45} or {Without A44} Ground circuit terminal 1 @ Component harness & Ground Connection
      • {With A45} or {With A44} Ground circuit terminal 24 @ 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 Window Switch at Door = Inactive
    • If not the specified state 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: M74P Window Motor - Passenger
    3. Test for infinite resistance between the test points:
      • {With A45} or {With A44} Signal circuit terminal 11 @ Component harness & Ground
      • {With A45} or {With A44} Signal circuit terminal 1 @ Component harness & Ground
      • {Without A45} or {Without A44} Signal circuit terminal 5 @ Component harness & Ground
      • {Without A45} or {Without A44} 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: M74P Window Motor - Passenger
    • Go to next step: If the specified state 
  6. Momentarily connect a 3 A fused jumper wire between the test points:
    • {With A45} or {With A44} Signal circuit terminal 11 @ Component harness & Ground
    • {Without A45} or {Without A44} Signal circuit terminal 5 @ Component harness & Ground
  7. Verify the scan tool parameter: Passenger Window Switch at Door = Up
    • If not the specified state 
    1. Ignition/Vehicle - Off & Remove - Jumper wire(s)
    2. Disconnect the electrical connector: M74P Window Motor - Passenger
    3. Ignition - On/Vehicle - In Service Mode
    4. Test for less than 1 V between the test points:
      • {With A45} or {With A44} Signal circuit terminal 11 @ Component harness & Ground
      • {Without A45} or {Without A44} Signal circuit terminal 5 @ 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:
      • {With A45} or {With A44} Signal circuit terminal 11 @ Component harness & Terminal 3 @ M74P Window Motor - Passenger
      • {Without A45} or {Without A44} Signal circuit terminal 5 @ Component harness & Terminal 3 @ M74P Window Motor - Passenger
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Replace the component: M74P Window Motor - Passenger
    • Go to next step: If the specified state 
  8. Momentarily connect a 3 A fused jumper wire between the test points:
    • {With A45} or {With A44} Signal circuit terminal 3 @ Component harness & Ground
    • {Without A45} or {Without A44} Signal circuit terminal 1 @ Component harness & Ground
  9. Verify the scan tool parameter: Passenger Window Switch at Door = Down
    • If not the specified state 
    1. Ignition/Vehicle - Off & Remove - Jumper wire(s)
    2. Disconnect the electrical connector: M74P Window Motor - Passenger
    3. Ignition - On/Vehicle - In Service Mode
    4. Test for less than 1 V between the test points:
      • {With A45} or {With A44} Signal circuit terminal 3 @ Component harness & Ground
      • {Without A45} or {Without A44} Signal circuit terminal 1 @ 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:
      • {With A45} or {With A44} Signal circuit terminal 3 @ Component harness & Terminal 7 @ M74P Window Motor - Passenger
      • {Without A45} or {Without A44} Signal circuit terminal 1 @ Component harness & Terminal 7 @ M74P Window Motor - Passenger
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Replace the component: M74P Window Motor - Passenger
    • Go to next step: If the specified state 
  10. Test for greater than 10 V between the test points:
    • {With A45} or {With A44} Signal circuit terminal 13 @ Component harness & Ground
    • {Without A45} or {Without A44} Signal circuit terminal 4 @ Component harness & Ground
    • If 10 V or less 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: M74P Window Motor - Passenger
    3. Test for infinite resistance between the test points:
      • {With A45} or {With A44} Signal circuit terminal 13 @ Component harness & Ground
      • {Without A45} or {Without A44} Signal circuit terminal 4 @ Component harness & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • Go to next step: If less than infinite resistance
    4. Test for less than 2 ohms between the test points:
      • {With A45} or {With A44} Signal circuit terminal 13 @ Component harness & Terminal 5 @ M74P Window Motor - Passenger
      • {Without A45} or {Without A44} Signal circuit terminal 4 @ Component harness & Terminal 5 @ M74P Window Motor - Passenger
        • If 2 ohms or greater - Repair the open/high resistance in the circuit.
        • If less than 2 ohms - Replace the component: M74P Window Motor - Passenger
    • Go to next step: If greater than 10 V 
  11. Test or replace the component: S79P Window Switch - Passenger

Test 3

    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: S79LR Window Switch - Left Rear
  3. Test for less than 10 ohms between the test points: Ground circuit terminal 7 & Ground
    • If 10 ohms or greater 
    1. Ground Connection - Disconnect
    2. Test for less than 2 ohms between the test points: Ground circuit terminal 7 @ 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 a test lamp turns On between the test points: B+ circuit terminal 8 & Ground
    • If the test lamp does not turn On and the circuit fuse is OK 
    1. Ignition/Vehicle - Off & Remove - Test lamp
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Verify the fuse is OK and there is voltage at the fuse.
    • If the test lamp does not turn On and the circuit fuse is open 
    1. Ignition/Vehicle - Off & Remove - Test lamp
    2. Test for infinite resistance between the test points: B+ circuit terminal 8 & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • If infinite resistance - Replace the component: S79LR Window Switch - Left Rear
    • Go to next step: If the test lamp turns On 
  6. Ignition/Vehicle - Off
  7. Connect the electrical connector: S79LR Window Switch - Left Rear
  8. Disconnect the electrical connector: M74LR Window Motor - Left Rear
  9. Connect a test lamp between the test points: Control circuit terminal 1 & Control circuit terminal 2
  10. Ignition - On/Vehicle - In Service Mode
  11. Perform the scan tool control function: Left Rear Window Motor

    Verify the test lamp state:

    Left Rear Window Motor - Stop = Test lamp Off

    Left Rear Window Motor - Up = Test lamp On

    Left Rear Window Motor - Down = Test lamp On

    • If not the specified state 
    1. Ignition/Vehicle - Off & Remove - Test lamp
    2. Disconnect the electrical connector: S79LR Window Switch - Left Rear
    3. Ignition - On/Vehicle - In Service Mode
    4. Test for less than 1 V between the test points:
      • Control circuit terminal 1 @ Component harness & Ground
      • Control 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 infinite resistance between the test points:
      • Control circuit terminal 1 @ Component harness & Ground
      • Control circuit terminal 2 @ 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 1 @ Component harness & Control circuit terminal 9 @ S79LR Window Switch - Left Rear
      • Control circuit terminal 2 @ Component harness & Control circuit terminal 10 @ S79LR Window Switch - Left Rear
        • If 2 ohms or greater - Repair the open/high resistance in the circuit.
        • If less than 2 ohms - Replace the component: S79LR Window Switch - Left Rear
    • Go to next step: If the specified state 
  12. Test or replace the component: M74LR Window Motor - Left Rear

Test 4

    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: S79RR Window Switch - Right Rear
  3. Test for less than 10 ohms between the test points: Ground circuit terminal 7 & Ground
    • If 10 ohms or greater 
    1. Ground Connection - Disconnect
    2. Test for less than 2 ohms between the test points: Ground circuit terminal 7 @ 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 a test lamp turns On between the test points: B+ circuit terminal 8 & Ground
    • If the test lamp does not turn On and the circuit fuse is OK 
    1. Ignition/Vehicle - Off & Remove - Test lamp
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Verify the fuse is OK and there is voltage at the fuse.
    • If the test lamp does not turn On and the circuit fuse is open 
    1. Ignition/Vehicle - Off & Remove - Test lamp
    2. Test for infinite resistance between the test points: B+ circuit terminal 8 & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • If infinite resistance - Replace the component: S79RR Window Switch - Right Rear
    • Go to next step: If the test lamp turns On 
  6. Ignition/Vehicle - Off
  7. Connect the electrical connector: S79RR Window Switch - Right Rear
  8. Disconnect the electrical connector: M74RR Window Motor - Right Rear
  9. Connect a test lamp between the test points: Control circuit terminal 1 & Control circuit terminal 2
  10. Ignition - On/Vehicle - In Service Mode
  11. Perform the scan tool control function: Right Rear Window Motor

    Verify the test lamp state:

    Right Rear Window Motor - Stop = Test lamp Off

    Right Rear Window Motor - Up = Test lamp On

    Right Rear Window Motor - Down = Test lamp On

    • If not the specified state 
    1. Ignition/Vehicle - Off & Remove - Test lamp
    2. Disconnect the electrical connector: S79RR Window Switch - Right Rear
    3. Ignition - On/Vehicle - In Service Mode
    4. Test for less than 1 V between the test points:
      • Control circuit terminal 1 @ Component harness & Ground
      • Control 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 infinite resistance between the test points:
      • Control circuit terminal 1 @ Component harness & Ground
      • Control circuit terminal 2 @ 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 1 @ Component harness & Control circuit terminal 9 @ S79RR Window Switch - Right Rear
      • Control circuit terminal 2 @ Component harness & Control circuit terminal 10 @ S79RR Window Switch - Right Rear
        • If 2 ohms or greater - Repair the open/high resistance in the circuit.
        • If less than 2 ohms - Replace the component: S79RR Window Switch - Right Rear
    • Go to next step: If the specified state 
  12. Test or replace the component: M74RR Window Motor - Right Rear
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