That relay is the sentry relay located in the fusebox under the second cover. It's what makes the blinkers flash when locking/unlocking. There are two contact points in this relay , one for right side and one for left side blinkers. One point on my relay was slightly bent causing only one side of the blinkers to blink. Opened up the relay, bent it back and now both sides blinker works when locking and unlocking. I don't think it has any other function.