I believe the voltage regulator is inside the altenator. What doesn't make sense to me is that it is clicking once then thats it.
Has the ignition switch ever been replaced that you know of? It was a recall back in the day on every major ford vehicle at the time. The dealer will no longer replace it as it is out of the recall time (the time has expired), but the part is cheap, like $10 bucks, and pretty easy to replace.
You will have to take the cover off the steering column, I think you may have to loosen the plastics around the dash also where the speedo housing is if I remember right, underneath the steering column is a large plug with a ton of wires going into it, undo the plug, and see if the plug is melted at all. When mine went it, it went out over time, and I lost a few things over a few days, such s blinkers and brake lights, then ac, and then the car just wouldn't start.
I guess that would be my next move.
93 5 Pointer. Cobra Chrome Rims, BBK Cold Air Intake, Electric Fan, BBK Headers with H Pipe and Flowmasters, MSD Ignition Goodies.