Hi AL514, it's me again. Hi CJ. I just got done whining to my former instructor, (who I replaced when he retired), that everything comes in pairs. I won't do a pair of struts for a month, then I get two strut jobs in one day. Two camshaft position sensors in the same day, etc. This has gone on for over 20 years and has spilled over to this site. We were just discussing a friend's Ford with an ignition switch problem an hour ago, then I answered an almost identical problem here a few minutes ago, and now this is the third one today!
You're right about the ignition switch. I never had one of these apart, but the same design is used on the older miserable Ford-built Escorts from the '80s. A former student had one of those that had a circuit that was dead. He bypassed that to get the car home from many states away. Once in town, it developed a constant-crank problem, not exactly like is described here, but similar. A new ignition switch solved the problem, then when we autopsied the old one, what we found was the lock cylinder turned a round plastic disc, and that disc had four raised rings that each had some ramps, or raised areas, molded in. Above each ring was the head of what looked like a half-inch-long plastic nail. Those were spring-loaded to push the head up so it made constant contact with the ring.
The point-end of the nail pushed on a spring-metal contact. There were four nails, each with a corresponding ring and contact. As the key cylinder was turned, those rings rotated and when a raised area came along, it pushed the nail against spring pressure, and the nail pushed on the contact. This was many years ago so my memory might be fading, but it seems to me one or more contacts was on when it was relaxed, and the nail pushing on it turned it off, while the nails for the others pushed on them to turn them on.
Regardless, what had happened was two of the contacts had been overheated numerous times, something Ford owners know all about, and two of those nails melted. One melted in such a way that it was too short to push the contact and turn it on. The other one melted while it had its contact turned on, and couldn't release under its spring pressure.
I'm not sure if this is the same problem, but given the description of the symptoms, I'd go with your assessment of needing a new switch.
Sunday, September 18th, 2016 AT 5:10 PM