I have replaced the alternator on my van and have a voltage regulator but where?

What is your question?

Where is it located? I cannot find it in the engine compartment and the only place left concealed is the dashboard and firewall behind it. Also have to ask, even though I was sold a freestanding VR, where is the "black box", computer, auto switching box or whatever you wish to call it. I have seen reports that this VR is a part of that and that there are more than one type of electrical system on vans of this year. The Alternator box said it was for external regulator and new alternator did not help with problem of NOT CHARGING. The VR I have is a 1" thick 4x5" metal can with one two wire connector and filled with black epoxy on the back side.