The contact owns a 2008 Chevrolet Silverado 3500. The contact stated that while the husband was driving, a warning message indicating the hood was unlatched had been displayed and the front headlights were not operable. Smoke was seen coming from under the hood and after lifting the hood to inspect the engine compartment flames and smoke were present. The husband extinguished the flames with water and the vehicle was pushed to a work sight. Upon inspection, it was discovered that the battery cable and electrical wiring harness were melted. The cause of the failure was not determined. The fire department was not called to the scene. The local dealer was notified of the failure. The manufacturer was not yet contacted. The failure mileage was unknown.