I have a 1999 Ram 1500 club cab.
My cruise control light would be on but when I set it the speed would not hold.
The problem was a hole in a plastic tube under the battery. The hole in the plastic tube connects to what appears to be a vaccum canister that is located underneath the battery.
I put electrical tape over the hole and it fixed my cruise control....the problem came back because the suction pulled the electrical tape in the tube and blocked the vaccum. I wound up cutting out the portion of the tube with a hole and spliced drip irrigation tubing over the existing plastic tube then used electrical tape to secure each end of the splice. My cruise control works great now.

 

I had that issue and the "Wild Vents" issue. It turned out there was a slice taken out of one of the metal lines for the CAD. I cut out that part of the line and patched it with some heavy duty vacuum line and small hose clamps. It works great now.

It took me forever to find that leak. I'd all but given up, and just noticed it out of the blue when I was doing an oil change. I was happier than **** to find that :P.

 

I had the same hole in the same place. I cut the plastic line at the hole and used a 2 inch piece of vacuum line to splice it together.