88 formula 305 tbi car,

just need a starting point to see why it wont engage i may be using the car for a long trip soon and cruise would be nice to have

My Iroc was the same way. I followed the diagnostic chart in the GM manual and found the multi function switch bad in mine, was about $80 from GM. In order to diagnose the problem, the GM manual suggest first to check your vacuum lines etc... and make sure you have vacuum to the transducer. After that it will have you start checking the electrical connections at the cruise module with ohm meter or test light. My cruise module was located up under the dash on passenger side, thanks to the guys on the board here that helped me locate that because the GM manual was very vague on where that turkey was. I don't have my manual handy at the moment so I can't post exact procedure but this should give you an idea of what will need to be done. Maybe someone here can post the diagnostic chart here for you, I have seen that done many times on here, some of these guys are pretty helpfull, hope this helps,,,,,Larry.

dont have a gm manual availible to me unfortunately......

however i noticed that the wiper circuit was missing its fuse, and i have it in my head that wipers and cruise are on the same fuse????

replaced fuse and wiper works but have not driven to see if cruise will work

Never thought about that, not sure if they are on the same fuse or not but sure sounds like a possability. Hope that works for you, it might be just that simple,,,, Larry.