Circuit/System Testing

WARNING: This page is about a different car, the 2012 Buick Verano. 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 S30 headlamp switch, ignition ON.
Test for B+ between the B+ circuit terminal 1 and ground.
- If less than B+
1. Ignition OFF, disconnect the X3 harness connector at the K9 body control module.
2. Test for infinite resistance between the B+ circuit and ground.
  - If less than infinite resistance, repair the short to ground on the circuit.
  - If infinite resistance
3. Test for less than 2 Ω in the B+ circuit end to end.
  - If 2 Ω or greater, repair the open/high resistance in the circuit.
  - If less than 2 Ω, replace the K9 body control module.
- If B+
Verify the scan tool LED Backlight Dimming Command parameter is greater than 40%.
- If 40% or less
1. Ignition OFF, disconnect the X1 harness connector at the K9 body control module, ignition ON.
2. Test for less than 1 V between the signal circuit terminal 9 and ground.
  - If 1 V or greater, repair the short to voltage on the circuit.
  - If less than 1 V, replace the K9 body control module.
- If greater than 40%
Install a 3 A fused jumper wire between the signal circuit terminal 9 and the B+ circuit terminal 1.
Verify the scan tool LED Backlight Dimming Command parameter is less than 30%.
- If 30% or greater
1. Ignition OFF, disconnect the X1 harness connector at the K9 body control module.
2. Test for infinite resistance between the signal circuit and ground.
  - If less than infinite resistance, repair the short to ground on the circuit.
  - If infinite resistance
3. Test for less than 2 Ω in the signal circuit end to end.
  - If 2 Ω or greater, repair the open/high resistance in the circuit.
  - If less than 2 Ω, replace the K9 body control module.
- If less than 30%
Test or replace the S30 headlamp switch.