How Does Power Door Locks Work?

 WORKING OF CAR POWER DOOR LOCKS

Power locks or electric locks allow the doors of a vehicle to be locked or unlocked automatically. A keyless entry remote control using a key fob can enable a user to activate the door locks from a short range outside the vehicle. The basic system components include: lock actuator, switches, wiring and a circuit breaker. Voltage is sent to the actuator by using a control switch which is connected to the 12 volt power source of the car through a circuit breaker.There are only a few main components of a power door lock system. Inside the car door, approximately behind the exterior door handle, is a metal latch that is the actual component that keeps the car door shut. A metal rod protruding from the bottom of the latch is connected to an actuator, which is a small motor that moves the latch up and down. Another metal rod protruding from the top of the latch is connected to the door lock button that sticks up at the top of the door. The exterior door handle is connected to a metal rod inside of the car door, but this rod engages with the latch only if the latch is in the "up" position. If the knob on the top of the door is pushed down or if the actuator is powered on to lower the latch, the rod connected to the door handle will disengage from the latch and will not be able to open the door.

Door Lock Actuator
In some cases a body controller is used in conjunction with the door lock system. The body controller can unlock and lock doors when a correct condition exist such as lock the doors after 2 minutes of driving. Most actuators are normally located below the door latch of the car or are manufactured as part of the door latch. When the door is unlocked the actuator is supplied with power which excites an electrical coil, electromagnetism supplies the force to actuate the door latch.
The actuator is the part of the power door lock system that makes it "powered." It has a metal or plastic exterior body, and its contents consist of a small electric motor, a series of gears and a small rack and pinion gear assembly. Electrical wires on the actuator's exterior connect it to both the car's primary power source and its computer system. When the computer system sends a signal to lock or unlock the door, it allows power to flow to the actuator. This makes the electric motor turn, which then causes a series of interlocking gears to turn along with it. The gears connect to a small, plastic rack and pinon assembly, which translates the cyclical movement of the gears to the back-and-forth movement of a plastic rod. When this rod moves up, it forces both the latch and the door lock knob to move up. When the rod moves down, it lowers the latch and the door lock knob.Some actuators are manufactured with an electric motor and a gear set is used to move a control rod to activate door lock. A series of gears act as a gear reduction to move a rack and pinion flat gear. The motor can be driven in both directions depending on the use of the switch to lock and unlock the door latch.