Re: 1998 crown vic PI with charging issues
First, Bert's correct, I shouldn't have had you disconnect the battery. I'm a dinosaur and tend to forget about the electronics. It sounds like your problem is in your field flash, but that's controlled inside the alternator. Since you've all ready burnt 3, I'd like to think that the problem lies elsewhere and that you're not getting ripped off by somebody.
Make sure that your grounds to your alternator are good and solid. According to the schematics, the alternator is grounded through it's own body to the engine. I've often seen where people will run a ground wire from the alternator to the main ground for the body. Make sure your point of contacts have been cleaned and give them a coating of dielectric grease. Make sure your belt is good, most parts stores will give away, or offer very cheaply a gauge for checking that the depth of the grooves of your serpentine belt have not worn too deeply. Also check that the idlers move freely in rotation as well as in flexing and that your bearings have not worn. Basically, you want to make sure that all the components, particularly those around the alternator, are free to move and not dragging down the auxiliary drive.
Chewing on asphalt and drinking dinosaur wine