Why is wiper switch HOT?

['74 Sport]

With the wipers on, the switch is VERY HOT to touch on Aaron's '74 Dart Sport. What is causing this?

Jerry

 

[dmoore]

Replace it before it melts down....its shorted internally.....Dave

 

[cudavert]

I'd say either high resistance through the switch or a wiper motor that's drawing too much amperage. Try a different switch and see what happens.

 

[RedFish]

Are the wipers on or been on ? High resistance from motor and linkage will heat the switch. The switch has a bimetal strip in it that will disconnect if it gets hot enough. This is meant to pretect the motor and switch when wipers are frozen to the glass. That bimetal strip will crack in half eventually. Its anyones guess as to how many heat / cool cycles before it cracks.
Also make sure the switch and the motor are well grounded.