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.
Check the 12 volt reference circuit pin 2 at the transfer case shift control switch for voltage with the ignition on.
- If less than battery voltage check the 12 volt reference circuit for an open or high resistance. If the voltage is low or non existent and the circuit tests good replace the BCM. If the BCM test good go to the next step.
- If the neutral indicator is on at all times check the neutral indicator control circuit for a short to ground. If the neutral indicator is inoperative during bulb check, check the neutral 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 neutral indicator off and on. If the neutral indicator is still inoperative short to neutral indicator control to ground, if the neutral indicator lights replace the module, program, and complete the motor learn procedure. If the neutral indicator is still inoperative replace the switch.