Here is some helpful info and tech on 98-02 vp44 24v Cummins engines.
Some standalone diagrams can be found on this site http://www.texstarntx.com/diy-24v-wiring-guide.html
If you do not have a engine harness / or ECM, for testing the VP44 can be started and ran ( but will not rev up) with a power 12V+ and a ground connected to terminals 6 and 7 as per the following diagram.
Here is a diagram for non dodge industrial engines ..
