3rd Gen Ram Tech2002-2008 Rams: This section is for TECHNICAL discussions only, that involve the 2002 through 2008 Rams Rams. For any non-tech discussions, please direct your attention to the "General discussion/NON-tech" sub sections.
I just changed my head gaskets and had to pull my engine apart so I know exactly where it is located. It is located on the bottom of the passenger side head towards the front (grill). The easiest way to get to it is to take off your passenger side heat sheild (the black cover where your wheel is) and it will be right there. Or you can just reach under there from the top of the engine also. You are going to unplug the wire attached to it and then it just pulls right out. Make sure you don't twist to get it out. Gently jiggle it back and for to get it lose. They are not cheap though... How do you know your's is bad?