BD Diesel 2 Low UnLoc 2001-2014 Chevy 2500-3500 4WD / 2001-2013 Chevy 1500 4WDInstallation is simple, the kit plugs in under the hood; No wire cutting or splicing; Kit comes with an illuminated rocker switch for control and to indicate when the front axle is being overridden; Designed to allow the operator to manually disable the front wheel drive mechanism by holding the hubs in the free (2WD) mode with the transfer case in 4WD low range; By allowing the front wheels to be disengaged, maximum torque is available to the rear