You hop in your Dodge diesel and turn the key only to be greeted with a click-click sound, instead of the more familiar whirring of your starter motor. Something is wrong. You somehow knew that the ...

Solenoids are everywhere. They open the water valve in your dishwasher, control the flow of gas in your stove, regulate ink delivery in printers, and play a crucial role under the hood of your car.

The opening part of this series laid out how the starter motor works, set the thing in the context of its electrical supply and suggested a few eyes-and-ears checks as the first steps in ...