* Actuator Motor Failure: The most common culprit is the trunk release actuator motor itself. This is the small electric motor located inside the trunk lid that physically unlocks the latch. A clicking sound often indicates the motor is trying to engage but is failing to turn. This motor can seize, wear out, or have a broken gear.
* Wiring Issues: Check the wiring from the button to the actuator. Look for broken, frayed, or corroded wires, especially where the wires enter the body and trunk. A poor connection anywhere along that path will prevent the current from reaching the actuator.
* Switch Failure: While you've ruled out the fuse, the button or switch itself in the door panel or on the key fob could be faulty. It might be sending a weak signal or not sending a signal at all, even though you hear a click which might be the switch making contact momentarily.
* Central Locking Module Problem: The car's central locking module (sometimes called the body control module) controls all the locking and unlocking functions. A malfunctioning module could be preventing the signal from reaching the trunk release actuator. This is less likely if the other locking features work fine.
* Ground Issue: A poor ground connection somewhere in the circuit can also cause intermittent or complete failure. Inspect the ground points near the trunk and in the car's electrical system.
Troubleshooting Steps:
1. Test the Actuator Directly: If you're comfortable with basic car repair, try bypassing the switch and wiring by directly applying 12V power to the actuator motor wires (with the correct polarity – check a wiring diagram for this, mis-wiring can cause damage). If it works, the problem is in the switch or wiring.
2. Check the Wiring: Visually inspect the wires leading from the switch to the actuator, both at the door and in the trunk boot area where they might be pinched or rubbed. Pay close attention to where the wiring enters the body and trunk lid.
3. Advanced Diagnostics: This may require a scan tool to check for error codes related to the central locking system or body control module. An auto parts store may be able to scan your car for free.
If you're not comfortable working on car electrical systems, it's best to take the vehicle to a qualified mechanic for diagnosis and repair. The cost of a professional diagnosis will likely be less than the time and potential frustration of chasing down an intermittent electrical problem.
