Hi, I got this post off of Diesel Forums 3rd Generation,

On another site a member posted this '03 service manual says:

"5.9L Diesel With Manual Trans.
The speed control system is fully electronically controlled
by the Engine Control Module (ECM). A
cable and a vacuum controlled servo are not
used if the vehicle is equipped with a manual
transmission and a diesel engine. This is a servo-
less system. The controls consist of two steering
wheel mounted switches. The switches are labeled:
ON/OFF, RES/ACCEL, SET, COAST, and CANCEL."

He bought the switches and it worked on his 04. I got the switches for my 03
today and it does work. It engages at min speed of 35mph. Two diff dealers
told me you couldnt add cruise, but they were wrong. The parts cost $46.91
delivered to the door from newmoparparts.com I hope this helps someone

I also put the switches on my 03 2500 Ram. Worked like a charm.

HEY THANK YOU THAT LINK FOR newmoparparts.com
just ordered my parts. Never found it with google, it returned too
many hits and I got poor result by clicking away at all the links. It
saved me70 mile round trip twice to get the parts, once to order, once
to pick up.
Thanks once again.