Car Troubleshooting

Why Does My Car Keep Locking And Unlocking Itself?

As a toddler mom, I’m no stranger to the car locking and unlocking itself when my son plays with the key fob while I unload the groceries. But, when the car locks and unlocks itself, that’s a whole other story.

In general, a central locking system’s electrical issues cause vehicles to lock and unlock themselves. Usually, the culprit is a faulty actuator losing electrical signals. Occasionally, worn-out wires or a faulty door sensor will engage and disengage car locks independently.

Most locking system problems require a mechanic to diagnose the actual source, but you can investigate to narrow down the cause. Find the answers you need on common causes of malfunctioning car locks and more below!

Causes of Malfunctioning Car Locks

Before exploring individual causes of malfunctioning car locks, it’s essential to understand the flaws found with the power locking systems of vehicles. While central locking systems are a boon to the modern world, making it easier to lock and unlock the entire car at once, their centrality is also a problem.

Older vehicles without power locks come with their problems, but when their door lock has a problem, it remains localized to one door. When a single electrical system controls multiple locks, the entire system goes on the fritz if a single part goes out of place. So, usually, if there is a problem with power locks, it impacts every lock on the car. 

Some common causes of electrical locking problems include the following:

Broken Lock Actuator

The lock actuator of a vehicle turns an electric signal into a mechanical movement. In short, it reads the electrical signal from the car and responds by physically locking or unlocking the car.

The actuator contains wires and gears that wear down over time and require replacement in well-used vehicles. Signs that the actuator is on the fritz include strange, loud noises coming from the locks when they engage, erratic locking and unlocking, and complete power lock failure. 

In general, a mechanic must resolve a broken lock actuator. Replacement requires taking apart the car door.

Blown Electrical Fuse

The central locking system of a car contains a large amount of wiring. Like a home electrical system, cars use fuses to protect the electrical components of the vehicle. When circuits overload with too much electricity, the fuses blow, protecting the vehicle from extreme damage.

A blown fuse disrupts the car’s electrical circuit, resulting in minor electrical disturbances, including lock mechanism issues. In general, a mechanic must replace blown fuses. Working with vehicle electrical systems is dangerous, and one wrong move can cause further damage to the car. 

Broken Wires

The average car in the U.S.A. contains over 50 pounds of copper wiring. Without the wiring, power locks would not exist. The wiring routes the electricity from the car battery to trigger the mechanical functions of the locks.

When wires wear down and fray, the electrical signals are disrupted, resulting in faulty locks that may lock or unlock themselves or stop working. Working with wires is a risky business. If you suspect wire damage as the culprit of your lock problems, have a mechanic investigate. 

Damaged Solenoid

Some car locks have a component called a solenoid similar to the actuator. The solenoid is a magnetic component that controls the latch of the lock. The solenoid pulls the latch back into the door when you press the “unlock” and latches when you push the “lock” button of the door or key fob.

A damaged solenoid will not latch or unlatch the door properly, leading to jammed locks or a door handle that won’t open the door. Solenoids require professional replacement. The solenoid sits inside the car door, and replacement or repairs require taking apart the door. 

Damaged Key Fob

Occasionally, the only cause of car locks on the fritz is a dead key fob battery or a fob with failing programming.

Key fobs receive special programming to work only for your vehicle; when that programming or the microchip in the fob fails, the locks stop responding to the fob. Usually, a mechanic or locksmith can help fix or replace a damaged key fob. 

Weather

The locking system of a vehicle is not entirely weather-proof. Ice or moisture can inhibit locks from opening or closing. 

Usually, a bit of lock de-icer or hand sanitizer applied to the lock solves the problem.

How Do I Stop My Car From Locking Itself?

Generally, the best way to stop a car from independently locking itself is to fix the cause of the problem. Because most car lock issues are electrical, any time the vehicle runs, the lock problem may spring up. Until you address the source of the problem, the locking problem will continue. 

Do Car Doors Normally Lock Automatically?

Sometimes cars do come with an auto-lock function. This feature is a safety asset. Auto-lock usually engages when a vehicle reaches a certain speed. Some cars also lock themselves after being turned off for a specific length of time as theft prevention. 

Can You Disable Automatic Door Lock Programming?

Some newer vehicles do come with the ability to turn off automatic lock programming. Check your key fob for a button that says “disable” and click it. That should deprogram auto-locking functions. Additionally, some vehicles have a programming code to turn off the auto-lock function. Some cars, like the Ford Focus, turn the auto-lock off if you follow the below steps: 

  1. Insert the key in the ignition and turn the car on.
  2. Click the “unlock” button on the door three times.
  3. Turn off the car.
  4. Press the “unlock” button three times.
  5. Turn the car back on.
  6. Wait for the horn to chirp to indicate programming mode has started.
  7. Press the “unlock” button, then press “lock.” The horn will honk, indicating that the auto-lock has deactivated.
  8. Turn the ignition off and wait for the horn to issue a confirmation honk indicating the approved programming change.

A Note on Disabling Automatic Door Lock Programming

Modern vehicles’ automatic door lock function may be a nuisance occasionally, but remember that the intent behind it is safety. Only deprogram automatic door locks if it is completely necessary.

If you choose to deprogram locks for a specific purpose, re-engage the locks as soon as possible, and definitely before driving with passengers in the vehicle. 

How Do You Reset Automatic Door Locks?

To reset the automatic lock function on your vehicle, you need first to follow the same steps used to deactivate it.

  1. Insert the key in the ignition and turn the car on.
  2. Click the “unlock” button on the door three times.
  3. Turn off the car.
  4. Press the “unlock” button three times.
  5. Turn the car back on.
  6. Wait for the horn to chirp to indicate programming mode has started.
  7. Press the “unlock” button, then press “lock.” The horn will honk twice, indicating that the auto-lock has re-activated.
  8. Turn the ignition off and wait for the horn to issue a confirmation honk indicating the approved programming change.
  9. Always test the locks to verify that the system has reset. If the automatic programming engages while driving, take the car for a short drive to confirm locks work. Or, if locks engage after the vehicle is off after a specific length of time, wait in the car until the locks engage to confirm programming has stuck.

Does Car Insurance Cover Lock System Damage?

Occasionally, car insurance policies do cover automotive lock damage. It depends entirely on the cause of the damage. If frayed wires are determined to have eroded from time and general wear and tear, insurance will not cover it.

But, if the damage occurs because of a hungry rat or rabbit, insurance may cover it. A call to your insurance agent will confirm coverage. 

How Do You Fix Central Locking Problems?

Generally, a DIYer should not try to fix central locking problems. The electrical system of cars is intricate and requires expert knowledge to repair without accidentally damaging the system. A certified mechanic or automotive locksmith can handle any central locking repairs needed for your vehicle. 

How Much Does A Door Lock Actuator Repair Cost?

Most lock actuator replacements or repairs cost between $250 and $350. The part itself ranges around $200, with the mechanical labor making up the remainder of the cost. 

How Much Does A Wiring or Fuse Repair Cost?

The extent of wiring or fuse damage determines the cost of the repair. A single fuse may cost around $100 to $150, while wiring ranges between $1,200 to $1,500.

How Much Does A Solenoid Repair Cost?

Solenoid replacement or repair generally costs anywhere between $200 to $700. The price change depends on the amount of labor involved in the replacement. More complicated doors cost more to repair. An everyday car model, like a Civic or Corolla, will cost less to replace than an exotic vehicle or sports car. 

How Much Does A Key Fob Repair Cost?

Key fobs generally cannot be repaired if programming has failed. Instead, the key fob needs replacing at a dealership or car locksmith. The complexity of the programming and rarity of the vehicle determines the cost. Most key fob replacements cost between $50 to $100. 

A Parting Note On Car Lock Problems

Car locks acting up are a nuisance. Because car lock problems usually point to electrical issues, don’t wait to get them investigated. Failed locking mechanisms make the car less safe and open doors (sometimes literally) for theft and costly repairs.

Find a reputable locksmith or mechanic to investigate your car’s central locking system before you become “locked” into a serious automotive problem. 

See also
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Welcome to my car seat blog! As a mom of 3, I put together with other hard-working moms a highly informative one-stop car seat resource, full with many reviews and buyer guides. I hope you find it invaluable. Thank you for trusting me & my team! - Keren