I did a bunch of checking with my local Volvo dealer, and through Email with a bunch of people on the net forums. The outcome was as follows. I had a company in West Los Angeles install a custom hitch and do the wiring using a comercially available unit that hooks to the battery and the cars lights. The company is Eckhart.com in the L. A. Area. Every thing works perfectly. The other email is on http://www.volvospy.com/frameset.php?bn=volvospy_s80.

This company makes a bolt on unit and a electrical unit similar to the one that worked for me http://www.draw-tite.com/compinfo/compinfo.htm.

I found this to be a really interesting exercise. Originally the people at Echarts said they could do it all no problem. Then in exploring other options just to see what else was available, another company said they would do the hitch but not the wiring. They were affraid to mess up the car's computer system. I then spoke to a very helpfull discount Volvo parts person at http://www.volvopartspeople.com/volvo/SearchProduct.asp?Model=S80&catid=318616359939162&year=00&productdesc=Trailer+Hitch (I wrote them for their phone number), who said I better use Volvo parts or I would mess up the computers. This really freaked me out. I didn't want a round expensive hitch with a 9 pin electical connection.

I spoke with my local Volvo service mangager and he let me speak with his installer. This fellow said he had worked at another dealer previous to mine and that he had, had a bunch of cars done at Eckhart's with excellent results. So, I went there and had excellent results.

Anyone that needs help can look at this info and if you still need help can write to me htkeys@linkline.com