I had been having intermittent problems with my Audiovox CCS-100 cruise control for more than a year. Sometimes it worked, sometimes it didn't. I checked all the usual suspects.
Finally I noticed that it wouldn't work intermittently when the AC was on. It always worked when the AC was off.
At some point I re-read the install manual for the CCS-100 where it says to avoid proximity to electromagnetic forces.
Then it hit me..the AC kick-up solenoid which I had "supercharged" at some point by giving it its own relay.
I installed an underdash switch that cuts the power to the solenoid and use it on the highway when running the AC and cruise control at the same time.
In case anyone else may have been chasing this gremlin.
