LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Buick >> 2012 >> Regal Base >> Repair and Diagnosis >> External Pages >> Different car >> Section 201 (Lighting System) >> Diagnostic Information and Procedures >> DTC B2740 >> Circuit/System Testing
July 1: So it begins. Don't worry, this is not in the correct legal jurisdiction!

Circuit/System Testing

WARNING: This page is about a different car, the 2011 Buick Regal. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the harness connector at the S30 headlamp switch.
  2. Ignition ON, verify that a test lamp illuminates between the 12 V reference circuit terminal 1 and ground.
    • If the test lamp does not illuminate, test the 12 V reference circuit for a short to ground or an open/high resistance. If the circuit tests normal and the circuit fuse is open, test the signal circuit terminal 12 for a short to ground.
  3. Verify the scan tool Front Fog Lamps Switch parameter is Inactive.
    • If not the specified value, test the signal circuit terminal 12 for a short to voltage. If the circuit tests normal, replace the K9 BCM.
  4. Install a 3 A fused jumper wire between the signal circuit terminal 12 and the 12 V reference circuit terminal 1. Verify the scan tool Front Fog Lamps Switch parameter is Active.
    • If not the specified value, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the K9 BCM.
  5. If all circuits test normal, test or replace the S30 headlamp switch.
scientia non olet · About LEMON Manuals