Circuit/System Testing

WARNING: This page is about a different car, the 2019 Buick Cascada, 2018 Buick Cascada, and 2017 Buick Cascada. However, it is still accessible from the selected car via links, so may be relevant.

Ignition OFF, exterior lamps OFF, remove the appropriate E4 Cornering Lamp bulb.
Test for less than 5 Ω between the ground circuit at the socket terminal and ground.
- If 5 Ω or greater
1. Ignition OFF.
2. Test for less than 2 Ω in the ground circuit end to end.
  - If 2 Ω or greater, repair the open/high resistance in the circuit.
  - If less than 2 Ω, repair the open/high resistance in the ground connection.
- Go to next step: If less than 5 Ω
Connect a test lamp between the control circuit at the socket terminal and ground, ignition ON.
Verify the test lamp turns ON and OFF when commanding the appropriate Cornering Lamp ON and OFF with a scan tool.
- If the test lamp is always OFF
1. Ignition OFF, disconnect the harness connector at the K26 Headlamp Control Module.
2. Test for infinite resistance between the control circuit and ground.
  - If less than infinite resistance, repair the short to ground on the circuit.
  - Go to next step: If infinite resistance
3. Test for less than 2 Ω in the control circuit end to end.
  - If 2 Ω or greater, repair the open/high resistance in the circuit.
  - If less than 2 Ω, replace the K26 Headlamp Control Module.
- If the test lamp is always ON
1. Ignition OFF, disconnect the harness connector at the K26 Headlamp Control Module, ignition ON.
2. Test for less than 1 V between the control circuit terminal and ground.
  - If 1 V or greater, repair the short to voltage on the circuit.
  - If less than 1 V, replace the K26 Headlamp Control Module.
Test or replace the appropriate E4 Cornering Lamp.