Intermittent cruise control not working properly

Hello, it sounds like you may have a section of the wiring harness that have worn through, and it sitting on a stub or a place (contact point) where the harness is moving, especially over bumps like you said. Another possibility is there's an intermittent issue with the body control module. It controls the cruise control. Is or has the check engine light been on at any point? I've added the circuit diagrams below, if you're up to testing some circuits. But do a good visual check first, don't move the harness at all, just look for places where there might be damage, or the plastic covering is coming apart. If you have the means to test the wiring circuits, we can talk you through that part. But let us know when you find.

https://www.2carpros.com/articles/how-to-check-wiring

https://www.2carpros.com/articles/how-to-replace-a-bcm-body-control-module

Just try not to move the harness too much, because you might move the problem area away from whatever it might be shorting out on. It's like accidently fixing it and you'll never find the problem after that.