Vehicle Lock Repair: what to note first

Pressing the remote locks three doors with a solid clunk and leaves the rear passenger door untouched, every single time. A twist of the key still opens that door by hand, so the fault is sitting somewhere between the remote and that one lock.

Worth answering before the call

Does the remote behave differently on that lock than the mechanical key does? Has the lock been getting stiffer gradually, or did it stop suddenly? Which lock is affected: a door, the trunk or hatch, or a storage compartment?

Why has my key fob suddenly stopped working?

A dead coin-cell battery is the most common reason, and it is a straightforward fix once the fob is opened. Less often, the fob has lost its pairing with the vehicle or its case has cracked and let in moisture, both of which a locksmith can check and address.

What is the difference between an actuator problem and a wiring problem?

An actuator problem usually means the small motor that moves the lock has worn out, though a switch or control signal in the same assembly can fail too. A wiring problem usually means the motor is fine but current is not reaching it, often traced to a cracked wiring boot at the door hinge or a corroded connector, though the locksmith checks the whole path rather than assuming which it is.