LED Dimming Circuit Test
WARNING: This page is about a different car, the 2009 GMC Sierra, 2009 GMC Cab & Chassis Sierra, 2009 Chevrolet Silverado, and 2009 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
- Ignition OFF, disconnect the harness connector at the appropriate component.
- Verify that a test lamp illuminates between the listed ground circuit terminal and battery voltage.
- Right steering wheel switch terminal 1
- Left steering wheel switch terminal 8
- DIC switch terminal 5
- Manual HVAC control module terminal 10 X2
- Multifunction accessory switch terminal 3
- If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
- Connect a test lamp between the listed LED dimming control circuit terminal and ground.
- Right steering wheel switch terminal 2
- Left steering wheel switch terminal 6
- Power take off switch terminal 6
- Trailer brake controller switch terminal 7
- IPC terminal 8
- Radio terminal 7 X1
- DIC switch terminal 4
- Manual HVAC control module terminal 1 X2
- Multifunction accessory switch terminal 4
- Command the dimming test high to low with a scan tool. The test lamp should turn from bright to dim when changing between the commanded states.
- If the test lamp is always off, test the control circuit for an open/high resistance or short to ground. If the circuit tests normal, replace the BCM.
- If the test lamp is always bright, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.
- If all circuits test normal, test or replace the appropriate component.