The cruise control on my new (to me) 300E with 118k miles on it is malfunctioning. When I attempt to set a cruise speed it immediately floors the throttle for a second and then surges pretty severely. I can't keep it on for more than a few seconds.

Can someone tell me the various components that comprise the CC system and where they're located? Are there any usual culprits that can cause this kind of problem? Any easy fixes to attmept first before digging too far into it?

Thanks