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 at the inside rearview mirror.
- Ignition ON, test for 9.8-10.2 volts between the keypad supply voltage circuit terminal 12 and ground.
- If less than the specified range, test the supply voltage circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the CIM.
- If greater than the specified range, test the supply voltage circuit for a short to voltage. If the circuit tests normal, replace the CIM.
- Test for 0 volt between the keypad signal circuit terminal 11 and ground.
- If greater than the specified range, test the keypad signal circuit for a short to voltage. If the circuit tests normal, replace the CIM.
- Test for 9.8-10.2 volts between the keypad supply voltage circuit terminal 12 and the keypad signal circuit terminal 11.
- If less than the specified range, test the keypad signal circuit for an open/high resistance. If the circuit tests normal, replace the CIM.
- Test for less than 5 ohms between the mirror ground circuit terminal 8 and ground.
- If greater than the specified range, test the ground circuit for an open/high resistance.
- Ignition OFF, disconnect the CIM X1 connector. Test for infinite resistance between the keypad signal circuit terminal 11 and ground.
- If less than the specified range, test the keypad signal circuit for a short to ground.
- If all circuits test normal, test or replace the button assembly.