Pitot Heat

[jhickam]

We are currently in the process of an annual on our 1973 337G and we found that the pitot heat was not operating. My question is what controls the heating element on the pitot tube assembly other than the panel mounted swith . Is it a themostat, timer or resistor or what. It stays on now after we reattatched the broken wire to the unit. It appears too hot to be safe to the point of smoking. Any ideas would be of great help.

Jim
N1871M