Re ran installer and all gsx vehicles and persons are black. request services and the approaching vehicles are completely black
I don't understand how this it's even possible.
If there was a problem with the xml files (the add-on.xml not being read), you wouldn't be able to even start GSX, because the modules wont't load, and the vehicles won't even appear if the folder for our objects which is referenced in the add-on.xml for GSX, and there would be lots of errors too. It's just no possible that textures were missing, since they are all in their own folders, together with the objects.
Try to clear the shaders cache, by removing this folder:
%LOCALAPPDATA%\Lockheed Martin\Prepar3D v4\Shaders
P3D is supposed to do this automatically when you install a new version, and while is doing this, all textures will be black, and they won't appear all at the same time, sometimes (depending how fast your system is) it could take minutes. Maybe your sim crashed while it was doing the shaders refresh, so it couldn't complete it, so now some class of objects are stuck in black textures.
Forcing a shader cache rebuild might help.