As Bingo posted. I would pull and check wires. The frozen switch is new but I had problems with the heating wire for my unit.
Yes I had the same thing (more or less) happen. Here is one of the pictures.
I would chase the cause and fix immediately to prevent possible fire.
Here is my post with pictures.
What I think happened is the screw because loose and only a couple of wires was carrying all the current which caused them to get hot like a toaster or heating element and burned.
It is easy to gain access and replace the bad parts.
Good luck and let us know if you need help.