The common "shotgun" approach is to replace the Vehicle Speed Sensor located on the top of the differential. But when that goes out, usually there's an ABS warning light, maybe it won't go into Overdrive, and possibly other symptoms. 
I know of one OP who got cruise working by cleaning the contacts in the steering wheel. Unclear to me if he took the wheel off, or was able to get the switch area out of it with the wheel in place.
BUT BUT BUT I would agree with doing that ONLY IF it does NOT have Driver Side AIR BAG. The pad in the center of the wheel should be marked "SRS" or "Air Bag" or the like. I don't think an E-Series as old as a '94 has SRS for Driver or Passenger, but check. You don't want to risk an uncommanded airbag deployment!