Brakes accidentally engaging

Recently we left for a trip with our 171.  It felt a little weird starting out and a couple miles down the road started smelling burning brakes.  We had never had the wiring for the brakes attached, so it seemed odd that they were engaging.  We brought it to our regular auto mechanic and he said that something else was electrically triggering the brakes.  Right now they've been disconnected, but we'd like to get them fixed, and wondered if anyone else has had a problem like this.  Any thoughts you have would be appreciated.

Yes, just like ToolmanJohn stated above, the RPOD is equipped with an emergency brake-away system. Most State Laws require this function. There is a small rectangular box attached to the frame up front with a cable and pin. The pin is inserted into the box and the cable runs up to the tow vehicle, often times attached with the safety chains. In the event of a trailer brake-away the cable pulls the pin on the box and engages the trailer brakes. It's one of the most important functions of the on-board RPOD 12v battery.