LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Cadillac >> 2018 >> CT6 Plug-In >> Repair and Diagnosis >> Body & Frame >> Windows >> Fixed And MOVEABLE Window System >> Diagnostic Information and Procedures >> Power Windows Malfunction >> Circuit/System Verification
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Circuit/System Verification

  1. Ignition - On/Vehicle - In Service Mode
  2. Perform the scan tool control function: Driver Window Motor - Up & Down

    Verify the component operates in both directions: M74D Window Motor - Driver

    • If not the specified state 

      Refer to: Circuit/System Testing - Test 1

    • Go to next step: If the specified state 
  3. S79D Window Switch - Driver - No Button Pressed

    Verify the scan tool parameter:

    • Left Rear Window Main Control Down Switch = Inactive
    • Left Rear Window Main Control Express Switch = Inactive
    • Left Rear Window Main Control Up Switch = Inactive
    • Right Rear Window Main Control Down Switch = Inactive
    • Right Rear Window Main Control Express Switch = Inactive
    • Right Rear Window Main Control Up Switch = Inactive
    • Front Passenger Window Main Control Down Switch = Inactive
    • Front Passenger Window Main Control Express Switch = Inactive
    • Front Passenger Window Main Control Up Switch = Inactive
    • If not the specified state 

      Replace the component: S79D Window Switch - Driver

    • Go to next step: If the specified state 
  4. Operate the component: Driver Left Front Window Switch - Pulled = Up & Release

    Verify the component works as specified: M74D Window Motor - Driver = Express Up

    1. Operate the component: Driver Left Front Window Switch - Pressed & Pulled

      Verify the component works as specified:

    • M74D Window Motor - Driver = Up
    • M74D Window Motor - Driver = Express Up
    • M74D Window Motor - Driver = Down
    • M74D Window Motor - Driver = Express Down
    • If not the specified state 

      Refer to: Circuit/System Testing - Test 2

    • Go to next step: If the specified state 
  5. Operate the component: S79D Window Switch - Driver-Left Rear Window Switch - Pressed & Pulled

    Verify the scan tool parameter:

    • Left Rear Window Main Control Down Switch = Active
    • Left Rear Window Main Control Express Switch = Active
    • Left Rear Window Main Control Up Switch = Active
    • If not the specified state 

      Replace the component: S79D Window Switch - Driver

    • Go to next step: If the specified state 
  6. Operate the component: S79D Window Switch - Driver-Right Rear Window Switch - Pressed & Pulled

    Verify the scan tool parameter:

    • Right Rear Window Main Control Down Switch = Active
    • Right Rear Window Main Control Express Switch = Active
    • Right Rear Window Main Control Up Switch = Active
    • If not the specified state 

      Replace the component: S79D Window Switch - Driver

    • Go to next step: If the specified state 
  7. Operate the component: S79D Window Switch - Driver-Right Front Window Switch - Pressed & Pulled

    Verify the scan tool parameter:

    • Front Passenger Window Main Control Down Switch = Active
    • Front Passenger Window Main Control Express Switch = Active
    • Front Passenger Window Main Control Up Switch = Active
    • If not the specified state 

      Replace the component: S79D Window Switch - Driver

    • Go to next step: If the specified state 
  8. Perform the scan tool control function: Passenger Window Motor - Up & Down

    Verify the component operates in both directions: M74P Window Motor - Passenger

    • If not the specified state 

      Refer to: Circuit/System Testing - Test 1

    • Go to next step: If the specified state 
  9. Operate the component: S79P Window Switch - Passenger - Pulled = Up & Release

    Verify the component works as specified: M74P Window Motor - Passenger = Express Up

    1. Operate the component: S79P Window Switch - Passenger - Pressed & Pulled

      Verify the component works as specified:

    • M74P Window Motor - Passenger = Up
    • M74P Window Motor - Passenger = Express Up
    • M74P Window Motor - Passenger = Down
    • M74P Window Motor - Passenger = Express Down
    • If not the specified state 

      Refer to: Circuit/System Testing - Test 3

    • Go to next step: If the specified state 
  10. Perform the scan tool control function: Left Rear Window Motor - Up & Down

    Verify the component operates in both directions: M74LR Window Motor - Left Rear

    • If not the specified state 

      Refer to: Circuit/System Testing - Test 1

    • Go to next step: If the specified state 
  11. Operate the component: S79LR Window Switch - Left Rear - Pulled = Up & Release

    Verify the component works as specified: M74LR Window Motor - Left Rear = Express Up

    1. Operate the component: S79LR Window Switch - Left Rear - Pressed & Pulled

      Verify the component works as specified:

    • M74LR Window Motor - Left Rear = Up
    • M74LR Window Motor - Left Rear = Express Up
    • M74LR Window Motor - Left Rear = Down
    • M74LR Window Motor - Left Rear = Express Down
    • If not the specified state 

      Refer to: Circuit/System Testing - Test 4

    • Go to next step: If the specified state 
  12. Perform the scan tool control function: Right Rear Window Motor - Up & Down

    Verify the component operates in both directions: M74RR Window Motor - Right Rear

    • If not the specified state 

      Refer to: Circuit/System Testing - Test 1

    • Go to next step: If the specified state 
  13. Operate the component: S79RR Window Switch - Right Rear - Pulled = Up & Release

    Verify the component works as specified: M74RR Window Motor - Right Rear = Express Up

    1. Operate the component: S79RR Window Switch - Right Rear - Pressed & Pulled

      Verify the component works as specified:

    • M74RR Window Motor - Right Rear = Up
    • M74RR Window Motor - Right Rear = Express Up
    • M74RR Window Motor - Right Rear = Down
    • M74RR Window Motor - Right Rear = Express Down
    • If not the specified state 

      Refer to: Circuit/System Testing - Test 5

    • Go to next step: If the specified state 
  14. All OK.
scientia non olet · About LEMON Manuals