I knew the switch was going bad so I ordered a new one. I decide to tackle the task today and this is what I find when I get the switch out.
Is the plastic plug end available from the dealership?

Geez that's the worst I've ever seen. looks like some circuit was dead shorted. You might have to put an ad in the appropriate wanted section here but it wouldn't hurt to call the dealer

I answered your ? in the truck section.

I just had that happen on my '88 Gran Fury. Believe it or not it was actually a little worse than that. I waited too long to replace the flickering switch (aftermarket POS that lasted a year). I bought a NOS switch, and snipped every wire and put a connector on each one and plugged each one into new switch without any plastic block. I didn't know what else to do. It's working fine and no connectors touch eachother so I think it's safe, just a pain in the butt to plug or unplug.

That is a drag. Putting your low beams on a relay and your high beams on a relay will SUBSTANTIALLY reduce the current flow through the headlight switch and prevent that from happening again.
The relays get located up on the radiator yoke (generally), left inner fender, or thereabouts depending on preference. Many have done it here - do a search.

Sorry about the damage to your harness. Hope your search for a replacement connector is successful.

That is NOT due to a short. That is due to excessive current through a loose connector, creating a LOT of heat...

The solution is to fix the loose connectors (it may be too late for those as heat will weaken them) and install relays.

The "Cause"?

https://www.youtube.com/watch?v=lODD63iMBJM&feature=youtu.be

Found it at O'Reilly.