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Summary
  • Possible reasons why your car door isn’t locking include problems with the key fob, such as a dead battery and a stuck button.
  • If the key fob is working, the door lock might not be working due to door lock actuator issues, a blown fuse, or faulty wiring.
  • While you can fix the issues yourself, it’s usually better to let a mechanic handle them, especially if you have limited knowledge of door lock mechanisms.

Your car’s door locks are crucial in keeping you safe and secure while driving and preventing break-ins. So if these parts start malfunctioning or stop working, it’s best to determine and address what’s causing the issue immediately.

Reasons Why Your Car Door Isn’t Locking

Here’s a quick way to narrow down what’s causing your door lock problems:

  1. If your door locks work with the switches on the doors but not with the fob, suspect the fob batteries.
  2. If just one of the door locks isn’t working but the others are, suspect the door lock actuator.
  3. If one of the doors is physically resisting being locked with the key or by hand, suspect a mechanical issue with the door latch assembly itself.
  4. Note that some door locks have relays operating the lock actuators and others simply have switches wired directly to the actuators. If just one switch doesn’t work, you might need a switch or some wiring repairs.
  5. If you’ve left your window down and it has rained on the switches a few times, expect the switches to be internally corroded. It happens.
, Power Door Lock Problems: Possible Causes and Fixes

Pro Tips are nuggets of information direct from ASE-certified automobile technicians working with CarParts.com, which may include unique, personal insights based on their years of experience working in the automotive industry. These can help you make more informed decisions about your car.

Pro Tip: Don’t buy a lot of parts before doing some troubleshooting. Door locks actuators depend on wiring and good connections. You might need to have a professional check for wiring issues if you get in over your head.

Here’s a list of parts that you may need to look at to diagnose the issue with your door locks:

Dead Key Fob Battery

When the key fob’s dead battery dies, the key fob can't broadcast the necessary signal to the central locking system to unlock or lock the doors.
When the battery dies, the fob doesn’t send a signal.

Fobs have an internal battery. Batteries die when they get old. Key fob batteries usually last between three and four years. When the battery dies, the fob doesn’t send a signal. If the battery is weak, the fob may only work when you’re really near the vehicle. Check the battery first if you can figure out how to open the fob and see which battery you need. Buy a battery, install it and see what happens.

Check the battery first if you can figure out how to open the fob and see which battery you need.

– Richard McCuistian, ASE Certified Master Automobile Technician

Malfunctioning Key Fob

If the key fob still can’t lock or unlock the car door after replacing its battery, the issue could lie in the fob itself.

The first thing you should check is the buttons, which could get stuck if you press them with too much force. One fix you can try is opening the fob, removing the chipboard, and realigning the stuck button(s).

However, note that usually this doesn’t work. If your fob has been abused (or it has gone through the washing machine), you’ll need to order a new fob, which may need to be programmed at a shop.

Other issues could also prevent the fob from sending signals to the lock. You can ask a mechanic to diagnose the problem. If it turns out that the best way forward is to replace the key fob, expect to pay between $15 and $500, depending on the model.

, Power Door Lock Problems: Possible Causes and Fixes

Pro Tips are nuggets of information direct from ASE-certified automobile technicians working with CarParts.com, which may include unique, personal insights based on their years of experience working in the automotive industry. These can help you make more informed decisions about your car.

Pro Tip: Usually, the older the car, the easier it is to find an inexpensive aftermarket fob online. Sometimes they come with instructions on how to program the fob.

Door Lock Actuator Issues

Each door lock has a door lock actuator, which may be faulty, but if that’s the case, you’ll just have one door lock that is inoperative. All the door lock actuators won’t die at the same time.

Besides a malfunctioning power door lock, other signs of a faulty actuator include erratic operation and strange noises from the bad actuator when you try to operate the locks.

A faulty door lock actuator usually requires replacement. On some vehicles, you can do it yourself. On others, it’s best to hire it done.

Whoever does it will need to remove the door panel, roll up the window, and reach inside the door to access the actuator, which may be attached to an integral bracket that is riveted or screwed to the inner door skin.

You can try to do it yourself or you can have a mechanic replace it. Be prepared to spend between $125 and $250 for the replacement piece and a bit more for the labor fee.

Blown Fuse

Like other electric car parts, the door lock has a fuse that provides overcurrent and short-circuiting protection to its circuit. To check the fuse you’ll need to consult your owner’s manual or look your vehicle’s fuse panel details up online.

When a component receives a surge of current beyond what it can handle, the fuse blows, disconnecting the circuit and protecting it from overcurrent. This prevents the door lock system from working.

That being said, sometimes fuses will blow just because they’re “tired.” But make sure when you replace the fuse, you use a good brand and not a cheap knockoff. Some of the really cheap fuses are really bad quality.

Faulty Wiring

Car door locks have wiring just like everything else, along with the connectors, terminals, etc. Wiring won’t usually be the issue, and you may have to hire somebody to check the wiring if you’re not good at automotive electrical.

Repairing or replacing the faulty wire is a task best left to a mechanic or a technician because pinpointing it is tricky. Handle the wrong wire, and you might make the problem worse or make other parts malfunction.

The Bottomline

If there’s no mechanical issue with one of the locks, you can lock all the doors mechanically if the electric locks don’t work. But a problem with the locks is always a safety issue, so it’s best not to take anything for granted. Check your key fob for issues, like a stuck button or dead battery.

If the fob is clear, the next best step is to take your vehicle to a mechanic. Blown fuses, door lock actuator issues, and wiring problems are usually tricky to address, especially if you’re not confident handling your door lock’s mechanism.

About The Authors
Written By Automotive and Tech Writers

The CarParts.com Research Team is composed of experienced automotive and tech writers working with (ASE)-certified automobile technicians and automotive journalists to bring up-to-date, helpful information to car owners in the US. Guided by CarParts.com's thorough editorial process, our team strives to produce guides and resources DIYers and casual car owners can trust.

Reviewed By Technical Reviewer at CarParts.com

Richard McCuistian has worked for nearly 50 years in the automotive field as a professional technician, an instructor, and a freelance automotive writer for Motor Age, ACtion magazine, Power Stroke Registry, and others. Richard is ASE certified for more than 30 years in 10 categories, including L1 Advanced Engine Performance and Light Vehicle Diesel.

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.

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