Circuit/System Testing

WARNING: This page is about a different car, the 2020 Buick Regal TourX, 2020 Buick Regal, 2019 Buick Regal TourX, and 2019 Buick Regal. However, it is still accessible from the selected car via links, so may be relevant.

Ignition OFF, and all vehicle systems OFF, disconnect the harness connector at the S48E Multifunction Switch - Center Console, ignition ON.
NOTE:
Verify interior lighting dimming is turned all the way up.
Test for 6.2 - 10.9 V between the dimming control circuit terminal 3 and ground.
- If less than 6.2 V
1. Ignition OFF, disconnect the harness connector at the K9 Body 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, refer to Interior Backlighting Malfunction .
- If greater than 10.9 V
1. Ignition OFF, disconnect the harness connector at the K9 Body Control Module, ignition ON.
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, refer to Interior Backlighting Malfunction .
- Go to next step: If between 6.2 - 10.9 V
Connect a test lamp between the control circuit terminal 17 and B+.
Verify the test lamp turns ON and OFF when commanding the Lane Departure Warning Indicator 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, ignition ON.
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.
  - Go to next step: 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.
- Go to next step: If the test lamp turns ON and OFF
Test or replace the S48E Multifunction Switch - Center Console.