I bought a water meth kit and I need to hook it up to the map sensor output wire. It has to be 5v output signal. It is a 2003 cummins. Can anyone help? This would be so nice seeing this is the last thing I have to complete.

 

On the driver's side of the engine, look where your injection rail is. On top of the manifold, you'll see two sensors with wire harness running to them. The one closest to the front of the truck is your rail press sensor, the one closest to the cab is the MAP sensor. Enjoy your water-meth!