Knowledge of basic auto electric would be helpful.
I did enlist help of a friend to confirm my suspicions. My vehicle, a 2009 Toyota Highlander, came with the "tow package kit". We were able to determine this did not include the modulator. I discovered the "kit" Toyota provided only had to do with a larger radiator and transmission cooler, nothing to do with the wiring. Once I determined that it was a matter of locating the location of the Toyota plug-ins. Finding them took longer than the actual instillation.