What is a Liftgate Lock Actuator?
If a car, van, or SUV has a liftgate, then it probably has an electric lock. Or more accurately, an electrically-actuated lock. The key can be used to manually lock and unlock the liftgate. But if the remote key fob or a switch inside the vehicle is to be used instead, something else has to turn the lock. The liftgate lock actuator is a solenoid (or, in some cases, a DC motor) that responds to an electrical signal and moves to work the lock mechanism.
How do Liftgate Lock Actuators work?
When a button is pressed on the key fob (or in the vehicle), a signal is sent to the Body Control Module (BCM) which, in turn, communicates with the liftgate lock actuator. The lock actuator is mounted, in some cases, between the lock cylinder and the lock and latch assembly. It is attached to the lock linkage (a cable or rod) inside the liftgate and responds to the signal from the BCM to move the linkage back and forth, to lock and unlock. Many newer vehicles have the actuator built into the latch assembly.
What are the symptoms of a bad Liftgate Lock Actuator?
There are a number of symptoms associated with a failing liftgate lock actuator. If the liftgate fails to lock or unlock at all with the electronic controls, the actuator may be bad. Normally (and depending on the type of actuator) a slight clunking sound or a whirring sound can be heard when the locks are activated. If the sound of the actuator becomes weak, excessively noisy, or it begins to make grinding noises, it could be failing. The lock may also move partially, but not all the way, indicating that it is going bad. Sometimes the lock actuator behaves erratically. If the doors lock and then unlock quickly - or they work intermittently - the lock actuator may be at fault. Each lock, in the doors and in the liftgate, has its own actuator. If one of them begins to work erratically, all of the locks may act in unison, making it difficult to know which actuator is the culprit.