Need Alternator Help
 

I am replacing the alternator on my 1992 400E. When I went to remove the old one, I found there was only one wire connected to it. There are two bolt posts and one blade on the back of it. The large post, marked B+, was connected, but the small post (D+) and the blade (W) are unconnected. There is an eye terminal hanging behind the alternator that fits onto the D+ post, but it was wrapped in electrical tape. Should I install the new alternator just as I found the current one? Should there be a ground connected to the blade? What is the D+ terminal for? Any help will be appreciated.