2005 Ford Explorer XLT V6 - 4x4 Hi blinking only drives in 2WD

Hi Everyone.  My 2005 Explorer XLT V6 4x4 will only drive in 2WD.  My friend said there is a good chance it could be the Transfer Case Control Module.  (There are a few different names for this part)  I watched youtube videos and there are none for a 2005. I looked behind the glove box and the lower foot panel and do not see a the Module, that was the location in 2003, 2003, 2004..  Is there one in the 2005??  If so, where is it?  Also, my friend hooked it up to his scanner and there were no ABS codes so he said it would need to be diagnosed by a Ford Dealer.  Can anyone tell me what the problem might be and how to fix it?  There is no strange noises.  It drives fine but just in 2WD (Rear wheels)  Please help.
PS - I called a Ford Dealership and they said the part is "Non Serviceable" whatever that means.