Circuit/System Testing
WARNING: This page is about a different car, the 2008 GMC Sierra, 2008 GMC Cab & Chassis Sierra, 2008 Chevrolet Silverado, and 2008 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 X3 at the appropriate door switch.
- Ignition ON, verify a test lamp does not illuminate between the supply voltage circuit terminal 7 and ground.
- If the test lamp illuminates, test the supply voltage circuit for a short to voltage.
- Ignition OFF, test for infinite resistance between the supply voltage circuit terminal 7 and ground.
- If less than the specified value, test the supply voltage circuit for a short to ground. If the circuit tests normal, test or replace the applicable rearview mirror face.
- Test for 5-10 ohms of resistance between the supply voltage circuit terminal 7 and the low reference circuit terminal 3.
- If not within the specified range, test the supply voltage circuit and the low reference circuit for an open/high resistance. If the circuits test normal, test or replace the appropriate rearview mirror face.
- If all circuits test normal, test or replace the appropriate door switch.