You probably have a broken speedometer cable. If the speedo doesn't work then that will kill the cruise control also. If the cable is not broken, the next thing to check is for a stripped gear in the box on the front wheel that the cable plugs into.
hi maxlife, definately a broken speedo cable, if its broken the cruise control doesn´t work either, my 1500 had the same problem last year, new cable, problem solved, good luck buddy, ps: shop around for a new cable, some thieving gits charge the earth!!!!!.:waving: