I tested out my cruise control, it still works perfectly; does that mean my ETA is fine?

Also, I haven't gotten around to testing those sensors yet, I will soon, but is it possible that if one or some of those are bad, that that's the source of the problem and I won't have to replace the wiring harness? I've searched for the harness online and it's around $800... a bit pricey for me at the moment.

Thanks guys.