Like Dave said, this just never really happens. How about this.............if you look directly at the solenoid, you should have the positive from the battery on the left (obviously, on the fat terminal) Next is the skinny stud that goes to the ignition switch and is triggered by the "start" position. The next skinny one is for the 12 volts that you feed to the coil to give it a hot starting voltage. And finally, the other fat one goes to the starter.

Not a lot to go wrong here. Maybe the starters are drawing too much an frying the insides of the solenoid?

Also, as Dave suggested, maybe go to Ford and try a different brand. But I have used even the most common Autozone type, and never get any failures, especially with the symptoms you are describing.

Try the ground thing, it is the only thing I see that could possibly cause some trouble.



Don