Same thing happened to me today after giving the XR6 a wash... Went inside and heard some honking and thought it was an idiot neighbour playing up - until I realised it was my car. Pressed all buttons on the remote but the horn kept honking randomly. Ended up tearing out the fuse and relay, and pulling the power on the entire car. It reset itself, I plugged the relay and fuse back in but the horn kept going for it. Taking it in for a pre-warranty check in a couple of days so hopefully they will find something!