I have 2011 Elantra that the cruise control is not working properly. It started out that I had to slap it to get it to work. I have to push the Resume button to turn on, Cancel button to set, set button to resume and the on/off button to cancel. Was told I need a new switch assembly. Done that and same problem. Shop checked brake light switch and said it was working properly, but I think they just meant for the brake light and it was not sticking. Even had steering wheel pulled and put dielectric grease on the wiring harness. Any ideas would be greatly appreciated.
Each button in the cruise control switch has a different resistor in it that is recognized by the computer. Your system reacting incorrectly to the button being pushed suggests that there is resistance in the circuit between the cruise switch and the computer, often the problem is in the clock spring.