I have fixed the cruise control in the Eldorado! In my case I needed new vacuum lines, as well as a new servo and transducer. I was able to source both from this eBay seller, who was knowledgeable and provided great customer service as I figured out what I needed. Wanted to share in case anyone is looking for similar parts.
https://www.ebay.com/str/celiafromthenutcompany86