I agree
If 2 GPS units won't charge, and you tried the same charge cable for each, it sounds like a charge cable issue. Did the 2nd unit have it's own charge cable, and if so, did you try it? Do you have the house charger cables and have you tried charging both units via house current?
On thing we continue to have trouble with is that the shape of some of the charge cable ends doesn't fit well in the cigarette lighter socket....sometimes even bending the metal contacts down inside the socket, blowing the fuse for the socket and whatever else is on that circuit (dome lights, horn, etc.). I've had to use tools to bend the contacts back into shape so the socket would again work, and would stop blowing it's fuse.