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HOMESERVICE MANUALSCHEVROLET2019EXPRESS 2500 BASE, VAN CARGO EXTENDED, 6.0L ENG VIN GREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 42 (FIXED AND MOVEABLE WINDOW SYSTEM)DIAGNOSTIC INFORMATION AND PROCEDURESPOWER WINDOWS MALFUNCTIONCOMPONENT TESTING
2019 Chevrolet Express 2500 Base, Van Cargo Extended, 6.0L Eng VIN G

Component Testing

2019 Chevrolet Express 2500 Base, Van Cargo Extended, 6.0L Eng VIN GSECTION Component Testing
WARNING: This page is about a different car, the 2018 GMC Savana 3500, 2018 GMC Savana 2500, 2018 Chevrolet Express 3500, and 2018 Chevrolet Express 2500. However, it is still accessible from the selected car via links, so may be relevant.

M74 Window Motor - Test

  1. Ignition/Vehicle & All vehicle systems - Off
  2. Disconnect the appropriate electrical connector: M74 Window Motor
  3. Connect a 25 A fused jumper wire between the test points: Control terminal 1 & B+
  4. Momentarily connect a jumper wire between the test points: Control terminal 2 & Ground

    Reverse the jumper wires 2 times between the terminals.

    Verify the component works as specified: M74 Window Motor = Up & Down

    • If not the specified state 

      Replace the component:M74 Window Motor

    • Go to next step: If the specified state 
  5. All OK.

S79P Window Switch - Passenger - Test

  1. Ignition/Vehicle - Off
  2. Disconnect the electrical connector: S79P Window Switch - Passenger
  3. Test for infinite resistance between the test points:
    • Ignition terminal A & Control terminal D - SwitchNot Pressed
    • Ignition terminal A & Control terminal H - SwitchNot Pressed
    • If less than infinite resistance 

      Replace the component: S79P Window Switch - Passenger

    • Go to next step: If infinite resistance 
  4. Test for less than 3 ohms between the test points:
    • Control terminal D & Control terminal F - Switch - Not Pressed
    • Control terminal H & Control terminal G - Switch - Not Pressed
    • If 3 ohms or greater 

      Replace the component: S79P Window Switch - Passenger

    • Go to next step: If less than 3 ohms 
  5. Operate the component: S79P Window Switch - Passenger - Pressed & Pulled
  6. Test for less than 3 ohms between the test points:
    • Ignition terminal A & Control terminal F
    • Ignition terminal A & Control terminal G
    • If 3 ohms or greater 

      Replace the component: S79P Window Switch - Passenger

    • Go to next step: If less than 3 ohms 
  7. All OK.

S79D Window Switch - Driver - Test

  1. Ignition/Vehicle - Off
  2. Disconnect the electrical connector: S79D Window Switch - Driver
  3. Test for infinite resistance between the test points:
    • Ignition terminal C & Control terminal A - SwitchNot Pressed
    • Ignition terminal C & Control terminal D - SwitchNot Pressed
    • Ignition terminal C & Control terminal G - SwitchNot Pressed
    • Ignition terminal C & Control terminal H - SwitchNot Pressed
    • If less than infinite resistance 

      Replace the component: S79D Window Switch - Driver

    • Go to next step: If infinite resistance 
  4. Test for less than 3 ohms between the test points:
    • Ground terminal F & Control terminal A - SwitchNot Pressed
    • Ground terminal F & Control terminal D - SwitchNot Pressed
    • Ground terminal F & Control terminal G - SwitchNot Pressed
    • Ground terminal F & Control terminal H - SwitchNot Pressed
    • If 3 ohms or greater 

      Replace the component: S79D Window Switch - Driver

    • Go to next step: If less than 3 ohms 
  5. Operate the component: Driver Left Front Window Switch - Pressed & Pulled
  6. Test for less than 3 ohms between the test points:
    • Ignition terminal C & Control terminal G
    • Ignition terminal C & Control terminal H
    • If 3 ohms or greater 

      Replace the component: S79D Window Switch - Driver

    • Go to next step: If less than 3 ohms 
  7. Operate the component: Passenger Window Switch @ S79D Window Switch - Driver - Pressed & Pulled
  8. Test for less than 3 ohms between the test points:
    • Ignition terminal C & Control terminal A
    • Ignition terminal C & Control terminal D
    • If 3 ohms or greater 

      Replace the component: S79D Window Switch - Driver

    • Go to next step: If less than 3 ohms 
  9. All OK.
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.