LEMON Manuals: Even more car manuals for everyone
Home >> Chevrolet >> 2020 >> Express 2500 LS, 6.0L Eng VIN G >> Repair and Diagnosis >> External Pages >> Different car >> Section 18 (Lighting System) >> Diagnostic Information and Procedures >> DTC B3445 >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2019 GMC Savana 3500, 2019 GMC Savana 2500, 2019 Chevrolet Express 3500, and 2019 Chevrolet Express 2500. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the X4 harness connector at the BCM.
  2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 4 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 X4 harness connector at the BCM and disconnect the harness connector at the CHMSL.
  4. Test for less than 5.0 ohms between the ground circuit terminal B and ground.
    • If greater than the specified range, test the ground circuit for an open/high resistance.
  5. Connect a test lamp between the control circuit terminal A and ground.
  6. Ignition ON, press and release the brake pedal. The test lamp should turn ON and OFF when pressing and releasing the brake pedal.
    • If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.
    • If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  7. If all circuits test normal, test or replace the CHMSL.
scientia non olet · About LEMON Manuals