Re: It's the...

The thermal time sensor is mounted in the t-stat housing, over the clutch.

The injector fan switch is an aluminum block bolted to the cam housing, rear side of the car, at the #1 cylinder. This switch does not come in contact with the coolant/antifreeze and couldn't be responsible for a leak. This switch is unlikely your problem - but it's the same switch that would run the carb cooling fan on the early models or injector fan on the later ones.

Are you referring to the sender shown in the top right of this picture? It is a little hidden by the braided line.