Any ideas on why my cruise control doesn't "set?" I can press the on/off switch and the cruise light comes on...then I press the set button and it doesn't set. I'm all ears!

1999 3500 4x4 5 speed

 

Mine did that too. Turns out that several wires in the steering column were too short, and had been pulled apart by using the tilt steering. Just a thought.

 

Well it runs off of vacuum so you might have a leak. The cruise control is on the driver’s side under your battery so look it over good to see any obvious problem. If your vacuum line is good try cleaning up your electrical connection. On a old truck that I got stuck in some deep water the cruise control went out totally so I had to got to Dodge and buy a new one. It isn't to bad I think it is under $100.

 

Try lifting up on the brake pedal with your foot while pushing the set button. The brake switch could be out of adjustment.

 

Mine did same thing.
The vacum line under the drivers side battery tray was melted in half due to leaking battery

 

Cruise will also fail to set when the speed sensor starts to go south as well.

 

Had similiar problems, ended up being broken wires from using the tilt everytime i get in and out of the truck. The plug is below the blinker on the column and only take a few minutes to check.

Jason