Circuit/System Testing
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2008 GMC Yukon XL, 2008 GMC Yukon, 2008 Chevrolet Tahoe, 2008 Chevrolet Suburban, and 2008 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.
- Ignition OFF, disconnect the CIM X1 harness connector and the inside rearview mirror.
- 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.
- 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.
- Reconnect the CIM X1 harness connector.
- Ignition ON, 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 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 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.
- If all circuits test normal, test or replace the button assembly.