What Cruise Control part do I need to replace?

What is your question?

Cruise doesn't work. Cable to throttle looked good. I checked the switch and it seems OK. The On and Set lights come on in the dashboard when I press those buttons. I assume this means the computer module is also OK, which would leave the servo assembly part: 189107B000. I've pulled this part off but can't tell if it is good or not. Can I test it somehow?