AWD LOCK (if equipped)
WARNING: This page is about a different car, the 2005 Mercury Mountaineer and 2005 Ford Explorer. However, it is still accessible from the selected car via links, so may be relevant.
The instrument cluster receives the AWD indicator status from the PCM. When all-wheel drive is selected, the PCM provides an indicator on command over the CAN circuits to the instrument cluster to illuminate the AWD LOCK indicator.