If you have a fuse blowing in any position in the fuse box you have a short somewhere the electrical system. to fix your problem you need to find the short. to find the short you will need a an electrical tester. you can make a tester out of an old light socket. take the old light socket and strip the wires back and take a wire coat hanger, cut off two pieces about four inches long and connect each wire to a piece of the coat hanger. bend the coat hanger over so the wire can't come off. tape the connections and you have an electrical tester. now: using your tester go to the rear of your vehicle and locate the wires that go to the lights in question. insert the prongs into the connecter of each light and see if the bulb blows when you turn on the lights. if it doesn't move to the other side and do the same. the bulb should blow. if it does then you have found your short. if the bulb doesn't blow continue checking the system until you find the short. I hope I have been of some help to you:
Mickey-G
August 2008