88 teg huh, that's a little old for my expertise, but I will tell you what I do know about honda cruise systems.
You need all of these things to work for your cruise to work:
clutch switch
vehicle speed sensor
brake switch (may or may not be seperate from your brake light switch)
power to the cruise control system
working cruise control unit and cable.
if youcan get the power to come on when you push the button, but cannot get the cruise to engage it is usually a failure with the clutch switch, VSS or the brake switch, reason being that if the clutch is pushed, or the brake is pushed, then it cancells the cruise system.
if the VSS is not working then the cruise unit has no idea how fast the vehicle is going, so therefore cannot keep it at that speed.
I checked my alldata and it doesn't give any hints or any information at all as where to start, jsut a list of componants, which are basically what I gave you above.