Circuit/System Testing

WARNING: This page is about a different car, the 2015 Buick LaCrosse. However, it is still accessible from the selected car via links, so may be relevant.

Ignition OFF, disconnect the harness connector at the S48D Multifunction Switch 2 - Instrument Panel, ignition ON.
Verify a test lamp illuminates when placed between the PWM voltage control terminal 3 and ground.
NOTE:
Verify vehicle interior dimming control is set all the way bright.
- If test lamp does not illuminate
  Refer to Interior Backlighting Malfunction
- If the test lamp illuminates
Connect a test lamp between PWM voltage control circuit terminal 3 and the control circuit terminal 8
Verify the test lamp turns ON and OFF while commanding the Lane Departure Warning Switch Indicator output control On and Off with a scan tool.
- If the test lamp is always OFF
1. Ignition OFF, disconnect the harness connector at the K109 Frontview Camera Module.
2. Test for less than 1 V between the control circuit and ground.
  - If 1 V or greater, repair the short to voltage on the circuit.
  - If less than 1 V
3. Ignition OFF.
4. 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 K109 Frontview Camera Module.
- If the test lamp is always ON
1. Ignition OFF, disconnect the harness connector at the K109 Frontview Camera 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.
  - If infinite resistance, replace the K109 Frontview Camera Module.
- If the test lamp turns ON and OFF
Test or replace the S48D Multifunction Switch 2 - Instrument Panel.