2002 Express 3500 Fuse Diagram - I would get a wiring diagram of both the instrument cluster and the automatic headlights (i think thats what you ment). Trace the power flow and make sure its getting power all the way through. it could just be a ground or power wire that has some high resistance or got pinched. not sure why you checked the wires between the obd2 port and then instrument cluster immediately. if you are getting. A brand of vehicle, Chevrolet or Chevy was produced by General Motors Company (GM). The car was named after Louis Chevrolet and was set up to sell a variety.