GMC Topkick (2003-2010) fuses and relays. The medium duty truck GMC Topkick was produced from 2003 to 2010. In this article, you will find fuse box diagrams of GMC Topkick 2006, 2007, 2008 and 2009, get information about the location of the fuse panels inside the car, and learn about the assignment of each fuse (fuse layout) and relay.