I just purchased a 2007 4x4 Sport Trac with the V8. In looking at 10-12 vehicles, I noticed some had a "Neutral Towing" button and/or indicator on the bottom of the console. Maybe you are referencing that this is what is on yours already. If so, you might want to contact one of the members in the link below in the forum about how to "engage" it.
When I looked it up for my curiosity, I found this item, part # 6L2Z-7H332-A. Looks like what you desire. Pricey, but a search on that part number shows some at several on-line dealerships.
One place I found.
Note that it will not work if you have the AWD option.
Have no idea if it's can be a DIY or needs to be dealer installed. I have the Ford Service Manuals and Wiring Diagrams for my 07. Can't find it the Shop manuals, but it is shown in the Wiring Diagrams.
There is a post in the forum about it here:
http://www.explorerforum.com/forums/showthread.php?t=294762
It also lists another possible source for the kit. Good Luck!
Edit: Found this elsewhere. If you have the kit already, give this a try!
The neutral tow kit is nothing more than a LED to indicate that the transfer case is in neutral. I installed my own LED and had the dealership download the program. This is for 2001 - 2005. The tow indicator light plugs into the small green connector under the steering wheel. I cut the connector off and installed straight line wire connectors and hooked it up to the LED. I had the dealer confirm that following the sequence of steps the transfer case was in neutral. Make sure the vehicle is secured (won't roll away)
1. have the engine running
2. put the shift level into neutral
3. turn the key back one position (off but not locked)
4. indicator light wil come on and then turn off
5. press the brake and the 4X4 auto button for about 5 seconds
6. the indicator light will flash 4 times and then stay on
7. release the brake and the 4X4 button
8. transfer case is in neutral
