Why does the car key's lock button not respond while the unlock button works?
3 Answers
The reasons why the car key does not respond when pressing the unlock button include the following: 1. The car key battery is dead: This is a very common situation, but quite difficult to diagnose. If the battery hasn't been replaced for a long time, this is likely the cause. Simply replace the battery. 2. Severe signal interference in the surrounding environment: Try moving the car to another location. If it works, it indicates strong signal interference near the car. If it still doesn't work, then it's one of the other reasons. 3. Control unit failure: The key's control unit is damaged. 4. Key code mismatch: This issue cannot be resolved by the owner and must be addressed at a 4S shop. 5. Key left inside the car: The key is left inside the vehicle (there is a key inside the car).
I've encountered this issue too! Last year, my father-in-law's car had the same problem. The lock button wouldn't respond no matter how much I pressed it, but the unlock button worked fine. After opening the key fob, I found the metal contact spring for the lock button was deformed and couldn't make contact with the circuit board when pressed. I temporarily fixed it by straightening the spring with nail clippers. Usually, you need to be careful not to drop the key, especially flip-style car keys – if dropped too often, the small internal components can get misaligned. Another possibility is water damage to the key fob, causing oxidation under the buttons and poor contact. If you open it and see green corrosion, cleaning the metal contacts with an eraser usually solves the problem. If all else fails, replacing the entire housing only costs about a few dozen yuan, and it's easy to DIY with parts bought online.
I've been repairing car keys for seven or eight years, and this situation is mostly an internal issue with the remote. The unlock button and lock button are two independent circuits. The most common problem with the lock button failing is oxidation of the button contacts or a burnt resistor on the circuit board. Just open the back cover of the key, dip a cotton swab in alcohol, and gently clean the black conductive rubber and the copper contacts on the circuit board. Remember to replace the battery before reassembling, as a voltage below 2.8V can easily cause partial function abnormalities. By the way, here's a little-known fact: in some car models, if the hazard lights are broken, it can also cause the lock button to fail because the lock signal needs to synchronize with the hazard lights.
