Thank you both!!
My dilemma is that I am traveling from Jacksonville, FL to Henderson, NC to pick up the trailer. I'm hoping to hitch it up, tow it about 7 miles to have new tires put on, brakes checked and bearings repacked then head back to FL. I won't have the tools or the time to re-wire the trailer in Henderson. What I think I will do is buy the 7 pin male connector with pigtail and the 9 pin connector (wife found them on the internet), take my voltmeter, Richard's great drawings, and a means to connect the pigtail to the 9 pin and give it a try. If that doesn't work, it could be a long day (week!?) camped at my cousins house. Back at the house I think I can do a better job of a weatherproof splice of the 7 pin into the trailer.
Reading the posts about open grounds, etc. I can't wait to troubleshoot a trailer that is new to me and has been sitting in storage over the winter. Electrons have never respected me and they are not about to start now.
Any suggestions about that?