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/Vehicle & All vehicle systems - Off
Disconnect the electrical connector: S48E Multifunction Switch - Center Console
Ignition - On/Vehicle - In Service Mode
Headlamp Switch = On
Verify a test lamp turns On between the test points: Control circuit terminal 3 & Ground
- If the test lamp does not turn On
  Refer to: Interior Backlighting Malfunction
- Go to next step: If the test lamp turns On
Ignition/Vehicle - Off & Remove - Test lamp
Connect the electrical connector: S48E Multifunction Switch - Center Console
Disconnect the electrical connector: X5 @ K9 Body Control Module
Ignition - On/Vehicle - In Service Mode
Headlamp Switch = On
Verify the component works as specified: Sport Mode - LED (Light Emitting Diode) @ S48E Multifunction Switch - Center Console = Off
- If the component does not work as specified
1. Ignition/Vehicle - Off
2. Disconnect the electrical connector: S48E Multifunction Switch - Center Console
3. Test for infinite resistance between the test points: Control circuit terminal 8 X5 @ Control module harness & Ground
  - If less than infinite resistance - Repair the short to ground on the circuit.
  - If infinite resistance - Replace the component: S48E Multifunction Switch - Center Console
- Go to next step: If the component works as specified
Connect a 3 A fused jumper wire between the test points: Control circuit terminal 8 X5 & Ground
Verify the component works as specified: Tour Mode - LED (Light Emitting Diode) @ S48E Multifunction Switch - Center Console = On
- If the component does not work as specified
1. Disconnect the electrical connector: S48E Multifunction Switch - Center Console
2. Test for less than 1 V between the test points: Control circuit terminal 8 X5 @ Control module harness & 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/Vehicle - Off
4. Test for less than 2 ohms between the test points: Control circuit terminal 8 X5 @ Control module harness & Control circuit terminal 13 @ Component harness
  - If 2 ohms or greater - Repair the open/high resistance in the circuit.
  - If less than 2 ohms - Replace the component: S48E Multifunction Switch - Center Console
- Go to next step: If the component works as specified
Replace the component: K9 Body Control Module