Cruise Control Not working on pete with C12

[Bandit]

Wasn't sure where to post this, so I will try here and let Rawze r moderator move if need be.

Here is the patients information:

99 Peterbilt 379
CAT C12

Problem : Cruise Control doesn't work.

Diagnostic work done so far.

1. Connected code reader to the truck. The on off switch reads and works correctly as well as the set/ resume switch. Checked the brake switches. I did not check the clutch switch as it showed working properly and the jakes work fine. No codes set, and the speedo works fine also, along with the brake lights.

2. While I was working on the truck, I noticed by accident if I had my foot on the brake pedal and held it there, the cruise control would work and raise the rpm.

3. I went under to the floorboard of the truck against the firewall. I found the fifth wheel, diff, low air warning, brake light switch and high water I think under there. They all work correctly.

I did some reading on line, and someone posted about a brake switch under the steering column cover behind the ignition. I found a switch, but it is marked for the parking brake, and matches what my wiring schematic said. I am not sure if that is a ground switch, and if it is stuck in the on position. I haven't had time to do anymore research or diagnosis, but hoping maybe someone has had r seen this problem before to lead me in the right direction.

Thanks ahead of time for any help or suggestions.