The cruise control for the '85 (and I think back to '81) uses a digital counter scheme. I am not familiar with the particulars, but I have seen the innards, and am sure of that much, judging by the parts used, etc... My original post a couple of months ago dealt with the earlier analog version, as found on my '78 and others. It uses an LM-2901, and a Cap/FET for storage of the set speed. The "newer" version probably uses TTL and a flip flop to store the set speed as a digital number. If your dad is over 35 years old, it may bring back waves of collegiate nostalgia. Good luck.