What you might get away with is folding over a small strip of sandpaper to slide under the contact to clean it up. Then, cut off the melted part of the pin and glue it back on with some RTV gasket sealer. That will let you build up the missing 1/16" or so of the pin to make it long enough.
I'm more familiar with Chrysler's products, but I'm sure Ford has the same stuff at their parts department. The black stuff stays more rubbery. The gray stuff gets harder and sticks to anything. Of course, you could use a pin out of the old switch if you still have it.
If you've added any electrical accessories, they might be overloading the switch contact. A simple way to prevent this from happening again is to use that contact to operate a relay, and use the relay contacts to power the circuit.
Sunday, March 7th, 2010 AT 6:05 PM