GM Performance Parts harnesses leave something to be desired when it comes to the fan setup. Installing this kit allows your GMPP controller to control two fans in off, low speed, and high speed operation! Extra relays and fuses install in the GMPP fuse block for an OEM looking install. Allows you to run powerful high performance fans such as Spal units. Comes with complete instructions on how to add our GMPP fan harness into your fuseblock, and also a downloadable HP Tuners file to enable the fans in your control module! Already have a fan harness but just need to be able to enable with AC? Check out our Hot Rod A/C Fan Speed Bump Circuit – link.