[Barnsnake]

I had a similar problem on a 2002 Explorer. Sometimes the cruise would not set. Light worked, just would never set. Next time it was driven it would work fine. Couldn't find the problem. After several months the HVAC started losing its settings after each shut off. I found an internet post that claimed a bad battery would cause that.
Out of desperation I replaced the battery that seemed to be working fine (cranked every time). The Cruise and the HVAC have been flawless since.