I have recently be experiencing problems with the cruise control on my 2011 Ultra Classic. Sometimes it engages, other times not. I've had the bike to my local HD dealer and they've run several diagnostic tests but have not determined the definite cause of this intermittent problem. They replaced the switch on the handlebars but it still hasn't solved the problem. Any suggestions on what might be causing this elusive situation? Thanks! RLJ50

 

One often overlooked problem is the brake light switches. The rear switch is the worst offender. If they fail then the Cruise control will not function.

 

Mine had similar issues. Would not engage consistantly and when it would it would randomly drop out. All diagnosticics checked out. On the recommendation of a friend I disconnected a wire from the roll off switch. Cruise has worked flawlessly (except no roll off) since. It's a quick, easy, restorable and free thing to try.
The switch is on the rear brake side under the tank near the fork. Its a wide area of the throttle cable with a sliding rubber boot and 2 wires with spade connectors. Just pull one off, doesn't matter which one.

 

The problem is the Roll off switch is very sensitive and for good reason. You want that cruise control to disengage at the slightest hint of a problem. You are cruising along with the cruise control set and your right hand is on the throttle grip and you twitch or twist the grip slightly and you cause the switch to disengage the cruise control.
I replaced the return cable twice before I gave up and now run without the roll off switch connected. Never had a problem. The brake lever is right there to disengage.

 

Very sensitive is an understatement. I usually only use cruise to relax and rest my right hand. The cruise would disengage with my hand completely off the throttle grip.
Either one of the brakes or the clutch will disengage the cruise. No issues as yet but I do have the warranty so will let HD replace the cable this fall. If that doesn't fix it then I'm good with leaving in disconnected.
While I agree the roll-off can be a good safety feature, in my opinion, too sensitive is a dangerous distraction that draws your attention from the road to trying to figure out why the cruise is randomly failing.

 

Any recent handlebar/control work on the "Right" controls, especially? Also, check the rear brake switch (ops/leak/damage)...two good reference points for starters.

 

The cables being adjusted to tight also will also produce cruise disengagement. A little extra slop is desirable.