[CREWZIN]

I don't know, it sounds simple to me. There were no problems before the installation of the remote starter, right? Now you have problems with electrical gremlins after the remote starter is installed. Weather or not they only installed part of the kit (starter only), it sounds like the rest of the kit is screwing things up. Now, how it's related to the rear wiper, maybe they pulled the voltage for the starter kit from somewhere around the rear wiper switch?

As MG just stated, if there's a separate fuse for the remote starter, pull it and see what happens.