Circuit/System Testing

2013 GMC Savana H1500, Van CargoSECTION Circuit/System Testing
  1. Ignition OFF, disconnect the X3 harness connector at the BCM.
  2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 3 and ground.
    • If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open high/resistance.
  3. Ignition OFF, connect the X3 harness connector at the BCM and disconnect the harness connector at the headlamp switch.
  4. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 15 and ground.
    • If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit test normal, replace the BCM.
  5. Verify the scan tool Dimming Control Signal parameter is less than 0.2 volts.
    • If greater than the specified range, test the signal circuit terminal 13 for a short to voltage. If the circuit tests normal, replace the BCM
  6. Install a 3A fused jumper wire between the signal circuit terminal 13 and the B+ circuit terminal 15. Verify the scan tool Dimming Control Signal parameter is greater than 2.75 volts.
    • If less than the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  7. Ignition OFF, disconnect the harness connector at the stop lamp switch.
  8. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal C and ground.
    • If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
  9. Install a 3A fused jumper wire between the signal circuit terminal D and the B+ circuit terminal C. Verify the scan tool Stop Lamp Switch Status parameter is 1023 Counts.
    • If less than the specified value, test the signal circuit for a short to ground. If the circuit tests normal, replace the BCM.
  10. If all circuits test normal, replace the headlamp switch.
RENDER: 1.0x

NO RELATED

Recommended Tools & Savings

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Affiliate disclosure: We may earn a commission at no extra cost to you.

When to See a Mechanic

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

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