2004 Explorer - Neutral Tow Feature - Not Working

On our 2003 Sport Trac it is nothing more than a light on a two wire lead that plugs into the wiring harness behind the dash, that notifies you have followed the proper procedure to get into "Neutral Mode". They no longer are sold by Ford, according to others posting on other forums. You could have a defective light or it might not be making contact at the plug connecting point on the harness.