I am a new 98 s70 owner, decent diy mechanic, cruise control does not work, fuse ok looking under the hood for a controller or module, suffering mechanical blindness, suggestions would be helpful, thank you.

 

check out volvowiringdiagrams.com to see the components. Could be the switch under dash (ie the brake disengage switch) or a speed sensor. Have you access to an OBD2 reader to check for codes?

Assuming your S70 is set up similar to the 850s, here's pretty good resource to get some understanding of how the system works. Note the codes listed are the OBD1 3 digit codes not what you'd see on an OBD2 reader

Volvo 850 cruise control