2004 GMC Envoy Liftgate Lock Cylinder Replacement Cost

A liftgate lock cylinder is the mechanism where the key is inserted in order to lock or unlock the liftgate on a car, van, or SUV. The lock cylinder connects by way of rods and cables to the lock and latch assembly that holds the liftgate closed. The cylinder will also actuate the central locking system of the vehicle, and maybe even the liftgate power window, if so equipped.

The liftgate lock cylinder is "coded" to the vehicle's key and it turns when the key is inserted and rotated, just like any other lock. But inside the liftgate, the lock cylinder is separate from the lock. It either moves a rod connected to the lock and latch assembly, or it triggers an electric motor that operates the lock. Usually, a single turn of the key will lock or unlock the liftgate, and a double turn slightly in one direction or the other will lock or unlock the whole vehicle. On some vehicles, holding the key all the way for a time will trigger the power window motor to lower the liftgate glass.

Most often, the symptom of a faulty liftgate lock cylinder is that the key will not turn or will not even insert into the hole at all. Sometimes the key gets stuck in one position or another, or it is difficult to remove. Occasionally a key is broken off inside the lock cylinder and cannot be removed. Electrical problems with the locking system or the power window are likely caused by the failure of other components.

Because most vehicles today that feature a liftgate also have electrically actuated locks and latches, a faulty lock cylinder may not be a big deal. A simple push of a button on a key fob will unlock the vehicle. No key needed. But sometimes, the lock cylinder is not the problem. Symptoms of a bad cylinder may also be related to a bad lock and latch assembly. If the lock mechanism is seized due to damage or corrosion, the key may not turn. In this case, the liftgate may cease to unlock or open at all and require a much more difficult and expensive repair. A vehicle can certainly be driven with a bad lock cylinder, but the problem should not be ignored for long in case the cylinder is not at fault.