With technological advancement, car locks have become much more user-friendly. Now, instead of inserting a key into a cylinder to unlock your car, you can simply press a button or even approach the vehicle with a fob or phone in your pocket. However, with this added technology comes increased complexity, making it more challenging to identify the source of a malfunction when issues arise.

If you’re experiencing difficulties with your car’s power locks, preventing you from entering or exiting the vehicle, here are six common reasons why your door locks may be malfunctioning.

Reasons your car door is not locking or unlocking

1. Key fob battery depleted.

   Swapping out the battery in the key fob could solve the problem. The batteries are typically of the coin type, but consult your owner’s manual for the exact type. (To find out, remove the dead battery from the fob; the battery size is usually indicated on the battery itself. You may need to refer to the manual or search online to learn how to open the fob.)

2. Blown fuse.

   Another simple fix could be a blown fuse. Before taking your car to a dealership, check the power door lock fuse to potentially avoid a costly visit. Your owner’s manual should guide you to the specific location of the fuse box, which is typically situated behind a plastic panel near your driver’s side footwell and can usually be removed without using any tools. Once the lid of the fuse box is taken off, the inside of the lid (or the owner’s manual) should feature a diagram showing the functions of different fuses. Look for the one corresponding to the door locks. You might need pliers or tweezers to extract it (some car manufacturers provide a pulling tool on the inside of the fuse box lid). Examine if the small metal squiggle in the center of the fuse is connected. A blown fuse will exhibit a visible gap. Make sure to substitute the fuse with a new one of the same amperage.

3. Key fob malfunction.

   Unfortunately, key fobs are more intricate than conventional keys. If the battery isn’t the issue, you’ll need to have the fob assessed by your dealer. They will connect it to a computer to verify if the fob is still transmitting the correct signal. If not, the fob will need to be replaced.

4. Solenoid malfunction.

   When you press the buttons on a key fob, it sends a signal to a solenoid inside your car doors. The solenoid converts the electronic signal into a mechanical action, such as moving a steel rod that was previously accomplished by turning a key in a keyhole. The solenoid within a door that isn’t locking or unlocking will need to be replaced, requiring the removal of the inner door panel.

5. Broken rod or connector.

   Although less likely than an electronic malfunction, there’s always the chance that one of the rods or, more likely, plastic connectors mentioned earlier has broken. This network of hardware connects the switches on the door panel with the inner and outer door handles and locks. Plastic can become brittle over time or accumulate gunk inside the door due to repeated opening and closing of the window. As with solenoid replacement, diagnosing and fixing this issue will necessitate the removal of the inner door panel, though any problems will be visible to the naked eye.

6. Electrical issues.

   If none of the aforementioned strategies resolve the problem, there may be an electrical malfunction. Each electrical component requires a logic board and a wire that can ultimately be traced back to a power source (the battery). A malfunctioning logic board or a break in the wire could be the cause. If the lock and unlock function operates intermittently, there may be an electrical short in the system due to the wear-down of the plastic insulation on the wire. If the system has completely stopped functioning, the wire may be severed.

It’s important to remember that most cars still have a physical key that can be utilized to lock and unlock the vehicle. It may be concealed in your key fob or provided as a separate backup that was included with the car. You can use this key to at least secure your car until you or a professional mechanic can address the issue.