Diagnostic Aids
WARNING: This page is about a different car, the 2009 GMC Yukon, 2009 Chevrolet Tahoe, 2009 Chevrolet Suburban, and 2009 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.
A short to ground on the neutral indicator control circuit will cause the neutral indicator to remain on at all times. An open or high resistance will cause the neutral indicator to be inoperative during the 2 second bulb check.