My Durango 4.7L (65k miles) is having a problem with cruise control. The CC will not even turn on. The "Cruise" indicator on the dashboard won't turn on no matter how firmly you press the button on the steering wheel to turn it on.
However, if I stop at a red light and cut the engine off, then crank it back up, there's a good chance that CC will work just fine.
If it will turn on initially, then I can turn it off and back on at will, and it will work perfectly for as long as the vehicle keeps running. The next time I start the engine, the CC may not work -- if so, it won't work at all unless I cut the engine off and back on again.
So it doesn't seem like the switch on the steering wheel -- maybe the BCM?