It took my dealer 6 hours to install my Jake Brake yesterday. He added lots of wiring and vacuum pump and new big belt. The control to turn on/off is on the gear shift. This thing works slick. It works all the way down to 750-800 rpms and the 48re downshifts as the truck slows. Will use it this weekend up on the BlueRidge. It cost me $1325. 00 plus cost of installation. I'll get photos later today. :-laf