My new 07 yells at me.

So I just joined taco world a week ago. I love my truck. It's an 07 double cab.
There is one thing though; she's a little naggy.

I don't know if it's a safety thing that I'm not aware of or what, but occasionally it will start honking at me. The first time I noticed it was when I got home Saturday. I hopped out to check the mail. I put it in park, but left it running with the door open. When I got back in, I put the seatbelt on, closed the door, and as I was driving up the drive way, it started honking. It wasn't a continuous honk; it was intermittent. I could hear the relay clicking under the dash.

It did it again today. I left it running while I went to check the kids out of after school care. This time, the door was closed while I went in. I came back out, got everyone loaded, threw it in drive, and it started again.

If I turn it off, then restart it, it stops, but best I can tell, it would continue honking for an eternity if I didn't. There doesn't seem to be a pattern either. Like I said, it's intermittent. The individual honks are timed about the same, but it will stop for a few seconds, then start again.

Anyone have any thoughts?