Looking for name of movie, 80s movie

Looking for the name of this movie. Saw it during the late 80s on TV so it must be older than that. I remember it is about a heist of some sort. A white semi trailer with the radio codename "Sundowner" is to be stolen. So they make a copy of the semi and the electronics to be able to simulate the original still driving the planned route. I think the original semi had some tricks built in like electronics and weapons. Actually this is all i remember about the movie. Have been looking for quite some time for it. Any help is appreciated.