1TONY1- I have researched this topic EXTREMELY well. Dig up some of my old posts about "05 changes" and you will see. I was contemplating putting a package together in order to add knock sensors to 03's and 04's.
The 2 Knock sensors in an 05 take 5V+ from the same sensor supply voltage as the rest of them, and each have an individual knock signal. The signal is given to pin 7 and pin 18 on the C3 PCM connector.
In order to add **** sensors to an 04, you will have to add knock sensor mounts, 2 sensors, an 05 engine wiring harness, an 05 PCM, and pick up an 05 C104 engine/chassis 20 pin connector. (have to buy elsewhere than Dodge)
The engine harness will plug right in to everything and supply your 5+V, however you will need to swap the connector for the flywheel sensor, as 05 want back to a crank sensor to save some $$. The 03/04s use a 14 pin c104 connector, so you will need to get a diagram to put the correct 14 wires into thir respective places on the chassis side into the 20 pin you will have to pick up. this will then plug into the new engine harness's 20 pin, of which 16 pins are used- 14 same as 04, +2 signals- DB/YL and BR/YL. Run the two signal wires to the correct pins from the C104 connector to the C3 PCM connector, and plug into the 2005 PCM.
Other option that simplifies the process, but adds cost is to swap the engine harness AND front chassis harness with 2005 parts. Then the only thing you have to deal with is adding the sensors themselves, and swapping the crank connector.