hooking up trailer brakes

I drive a 2003 Itasca Suncruiser on a workhorse chassis. It has the 8.3 GM V8 engine. I need to hook up a trailer brake controller. I was told that there may be a connector under the dash that with the proper adapter can just be plugged in to the controller negating the need for a complete rewiring. Anybody no where the connector is under the dash? Thanks