Circuit/System Testing
WARNING: This page is about a different car, the 2008 Buick LaCrosse and 2008 Buick Allure. However, it is still accessible from the selected car via links, so may be relevant.
I/P Dimming Lamps Circuit Test
- Ignition OFF, disconnect the harness connector at the appropriate component.
- Test for less than 10 ohms between the ground circuit terminal listed below and ground:
- Instrument Panel Cluster (IPC) - Terminal 1
- Driver Information Center (DIC) - Terminal 4
- PRNDL Lamp (Console Shift) - Terminal B
- HVAC Control Module (CJ2) - X1 Terminal A6
- HVAC Control Module (C67) - X1 Terminal B6
- Radio - X1 Terminal B5
- Headlamp Switch - Terminal 13
- Driver Window Switch - X2 Terminal B
- Driver Door Lock Switch - Terminal B
- Passenger Window Switch - Terminal C
- Passenger Door Lock Switch - Terminal B
- Outside Rearview Mirror Switch - Terminal B
- Right Steering Wheel Control (UK3) - Terminal 1
- Left Steering Wheel Control (UK3) - Terminal 8
- If greater than the specified range, test the ground circuit for an open/high resistance.
- Connect a test lamp between the appropriate signal circuit terminal and ground:
- Instrument Panel Cluster (IPC) - Terminal 13
- Driver Information Center (DIC) - Terminal 1
- PRNDL Lamp (Console Shift) - Terminal A
- HVAC Control Module (CJ2) - X1 Terminal A5
- HVAC Control Module (C67) - X1 Terminal B5
- Radio - X1 Terminal B4
- Headlamp Switch - Terminal 14
- Driver Window Switch - X1 Terminal F
- Driver Door Lock Switch - Terminal A
- Passenger Window Switch - Terminal B
- Passenger Door Lock Switch - Terminal A
- Outside Rearview Mirror Switch - Terminal E
- Right Steering Wheel Control (UK3) - Terminal 2
- Left Steering Wheel Control (UK3) - Terminal 6
- Ignition ON, command the Incandescent Dimming ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
- If the test lamp is always OFF, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
- If the test lamp is always ON, test the signal circuit for a short to voltage. If the circuit tests normal, replace the BCM.
- If all circuits test normal, test or replace the component.
Dimmer Switch Circuit Test
- Ignition OFF, disconnect the harness connector at the headlamp switch.
- Ignition OFF, test for less than 10 ohms between the low reference circuit terminal 1 and ground.
- If greater than the specified range, test the low reference circuit for an open/high resistance.
- Ignition ON, test for 9.8-10.2 volts between the 10-volt reference circuit terminal 10 and ground.
- If greater than the specified range, test the 10-volt reference circuit for a short to voltage. If the circuit tests normal, replace the BCM.
- If less than the specified range, test the 10-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
- Verify the I/P dimming lamps are at their lowest intensity.
- If the I/P dimming lamps are not at their lowest intensity, test the signal circuit terminal 9 for a short to voltage.
- Install a 3A fused jumper wire between the signal circuit terminal 9 and the voltage reference circuit terminal 10. Verify the I/P dimming lamps are at their highest intensity.
- If the I/P dimming lamps are not at their highest intensity, test the signal circuit for a short to ground or an open/high resistance.
- If all circuits test normal, test or replace the headlamp switch.