02 ford escape horn honking

I did a remote starter in an 02 Ford Escape. i installed just a remote starter a compustar and now the customer is telling me that the factory horn is going off for no reason. I connected the factory disarm wire and i checked it so that is not the case. When i installed the remote starter i didnt connect the horn to it so its not the remote starter doing it. The customer says that out of no where it starts to honk when no buttons are pressed on it and if they remote start the car it starts fine then when they unlock the doors and get in then the horn starts going off. Any info is appreciated.Confidence is the key to any project!!

Did you hook up dome light supervision?Installer, IT support, and FFL. I need less hobbies.