this is on an 06 3500 auto.

when i hit the on button the light on the dash comes on saying cruise.

then when i go to set the cruise speed nothing happens...

where should i start? i have no clue.

 

I'd begin by checking the brake light switch and the connector.

Has anyone done any work on the truck since this cropped up?

 

Whats there to check on the brake light switch? I just got my 06 2500 yesterday and have the exact symptoms. I love cruise control, especially since my 95 didn't have it.

 

I had the dash out on my 06. After that everything worked but the cruise control (brake lights worked).

It turned out the plug wasn't in quite all the way on one side, which wouldn't allow the cruise control to set.

 

try disconnecting both batteries , aka (master reset) , the same thing happened to me on a long trip. after returning home i performed the (master reset) and the cruise was back. i guess i let the gremlin out of the system!

 

Were/are you showing any codes? like a P0573 "High Voltage Detected At The Brake Switch" AKA get your foot off the brake pedal or you need a new brake switch.. My 05 just did the same thing on a recent trip..

 

The brake light switch deactivates the cruise.

 

Actually, I was kinda curious as to how it can't be installed correctly. As in seated wrong? From feeling around back there, It seemed like it was a bolt or two into the back of the pedal and I couldnt figure how it'd seat wrong. (I was looking at the wrong switch at that)

Edit: I got a new switch installed tonight. Here's my current problem. When i first installed the new swtich I had no brake lights. So, on the end of the switch is a small switch which has about a 90 degree sweep. I went from 0-90 degrees and I no have brake lights. The problem is, to get the brake lights, I have to depress the brakes about half way, as opposed to tapping them. The cruise control does work. But again, to disengage i've gotta really lay into the brakes. Where's the problem lie now?

Thanks again