1997 Cruise control

I have a 97 3500 that I cannot get the cruise control to work.
I have followed all the troubleshooting in the factory manual.
New clock spring and control switches.
The little green light will light up (but you cannot turn the light off until you shut off the truck)
Using a snap on scanner to read the PCM the buttons do exactly what the service manual says they need to do for voltage.
The servo is connected and tests out good. You can hot wire it and get it to function.
The wires all have continuity throughout the entire system.
I am stumped! Could the PCM be junk?
I followed the factory service manual troubleshooting step by step and technically it should be working.

Vacuum leak?

I figured it out! There had been some re-wiring done for the plug that connects to the clock spring. The sensor ground and one of the commands were switched. Put them back to their rightful place and BAM! It all works great.