A 4×4 actuator is an electronic device used to engage the front differential on a so-equipped, four-wheel drive vehicle. Not all types of four-wheel drive vehicles use this type of switch. The vehicles that do employ this type of actuator will also require a switch on the vehicle’s dash to be turned to a four-wheel drive setting. It is not unusual for the 4×4 actuator to require several seconds to fully engage the front axle on the four-wheel drive setting.
On some types of four-wheel drive vehicles, the operator is simply required to pull a shifter-like lever, typically located on the vehicle’s floor, to engage the front axle. This type of system is known as a manual, four-wheel drive system. On other types of vehicles, the operator is required to turn or push a switch on the vehicle’s dash in order to activate the front axle of the vehicle and the four-wheel drive system. This is commonly known as an automatic system. The problem with this type of system is that the axle can often take from several seconds up to a minute or more to lock the axle into gear.
The delay in engagement can often result in a vehicle becoming stuck or trapped in snow, sand or any other type of obstruction that warranted the use of four-wheel drive. The 4×4 actuator in some vehicles is a thermal-type switch that requires the switch to warm up prior to engagement. Some manufacturers offer a fully electric replacement switch that does not require a warming period, thereby allowing the actuator to engage the front axle immediately when the switch on the dash is activated. For the serious off-roader, this is often a very useful conversion.
Some vehicles use a vacuum-operated, 4×4 actuator that can develop problems locking the front axle over time. The cure for this is to replace the vacuum switch or to install a manual conversion system. Many owners of the vacuum 4×4 actuator choose to convert to a fully manual system that engages the front axle instantly when called to do so. This type of conversion is very popular with hunters and off-road enthusiasts who frequently find their vehicles in four-wheel drive in order to get out of a particular area. Most manufacturers of the vacuum and electronic thermal type of 4×4 actuator recommend that the switch be engaged periodically when driving the vehicle to avoid sticking situations caused by non-use of the system over long periods of time.