Thanks for the responses.  I will be looking for that 3rd wire harness.  I am sure that will do the trick. 

If it's similar to the UF600 there is a Youtube video by CF Moto USA/Curren RV that walks you through it. I did mine about a month ago.

I can't seem to locate the video by Curren RV.  I am thinking its no longer on their page.  There are two wire harnesses that plug into the rocker switch and I tried them both. At the other end I located the wire where the horn connects but once all together and with machine started the horn does not work. Am I missing something?  Would be great to see a video or have instructions.

I purchased the horn kit for the Uforce 1000 XL.  Wish it came with instructions.  Has anyone completed this task?HORN ADAPTOR CABLE, CFMOTO OEM – 5HYV-150191-2900
HORN SWITCH, CFMoto OEM – 5ASV-169040-6001
ELECTRIC HORN, CFMoto OEM – 6060-150600