Circuit/System Testing
WARNING: This page is about a different car, 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.
Check the interior dimming circuit pin 2 at the transfer case shift control switch for voltage for the 2 seconds after turning the ignition on during the bulb check.
- If less than battery voltage check the interior dimming circuit for an open or high resistance. If the voltage is low or non existence and the circuit tests good replace the BCM. If the interior dimming circuit and BCM test good go to the next step.
- If the AWD indicator is on at all times check the AWD indicator control circuit for a short to ground. If the AWD indicator is inoperative during bulb check, check the AWD indicator control circuit for an open or high resistance or short to voltage. If the circuit checks good continue to the next step.
- With the ignition on shift the transmission to neutral and using transfer case output controls attempt to command the AWD indicator off and on. If the AWD indicator is still inoperative short to AWD indicator to ground, if the AWD indicator lights replace the module. If the AWD indicator is still inoperative replace the switch.