The winch solenoid is an electronic device used to activate the winch motor on a vehicle-mounted winch. Created to withstand the high draw of electricity required to crank the winch, the winch solenoid is designed to supply the required current without damaging the winch switch or the winch motor. The winch solenoid is an electromagnetic switch that is activated when current from the battery is directed to the solenoid by pressing the activation switch. The activation of the solenoid sends current to the winch motor and the motor begins to turn the winch drum. The typical winch uses separate solenoids for forward and reverse, with the strongest winches using four solenoids.
The electric, vehicle-mounted winch motor is nothing more than the same engine starter motor used on many vehicle engines. Like the starter that is used to crank a vehicle's engine, the winch motor requires the use of a solenoid to send the proper amount of current to the motor. A common winch uses a separate winch solenoid to move the winch drum in and out. On the strongest winches, which is commonly series-wound, has a four-winch solenoid arrangement and is commonly used with two solenoids working in unison for both winch directions.
Depending on the winch manufacturer as well as the winch style, the winch solenoid can be either mounted on the winch or in a remote location. When mounted on the winch, the winch solenoid is commonly mounted above the winch motor. This eliminates extra wiring and reduces the opportunities for chaffing a wire and creating a short in the winch's electrical system. Remote-mounted solenoids, while more complicated, protect the solenoids from excessive heat created by the winch motor. This can often save the winch from shutting off in the midst of a pull due to the overheating of the winch solenoid.
Another plus to having remote-mounted solenoid switches on any winch is space savings. By removing the winch solenoid from the top of the winch motor, the winch becomes a smaller package and requires less room to mount. A smaller winch is more easily hidden behind a bumper or brush guard, and is also more easily protected from damage. Many winch failures are directly related to damage incurred while traveling on trails and encountering rocks, tree limbs and other debris that damages the solenoid. Protecting the solenoid allows the winch to be relied on and operational when use is required.