Circuit/System Testing

2011 Chevrolet Chevy Express G3500, Van Cargo Extended, 6.6 LSECTION Circuit/System Testing
  1. Ignition OFF, disconnect the GPS and cell coax cable connector at the vehicle communication interface module.
  2. Using the EL-49903-5 adapter with EL-49903-4 coax cable, connect the EL-49903  to the vehicle communication interface module, place the test antenna on the roof of the vehicle.
  3. Ignition ON, wait 5 minutes, then contact the OnStar call center consultant by pressing the blue OnStar button. A call center consultant should answer the call, ask the consultant to verify the vehicle location to confirm the GPS system is functioning.
    • If the OnStar GPS does not function, replace the vehicle communication interface module.
  4. Ignition OFF, perform the coax cable test on the coax cable, refer to Component Testing . The coax cable should pass the test.
    • If the coax cable does not pass the test, replace the coax cable.
  5. If all circuits test normal, replace the cellular and digital radio antenna.
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.