How to Deal with Buick Excelle Door Auto-Unlocking Issue?

[LeCollin]

Open the driver's side door of the Buick Excelle. If the anti-theft system of the Buick Excelle is locked, press the door unlock button for 3 seconds. Depress the brake pedal of the Buick Excelle. Press the one-touch start button of the Buick Excelle to start the engine. The dashboard will light up, indicating that the Buick Excelle's engine has been started. Hold down the door unlock button of the Buick Excelle for 3 seconds to unlock the door.

[ValeriaLynn]

I encountered the same issue last time when driving my old Buick Excelle. After struggling for a while, I found it was caused by a stuck central locking relay. This problem is particularly common, especially in vehicles over ten years old. It could be either relay contact burning and sticking, or aging return springs in the door lock actuator motors. Another possibility is water intrusion or program malfunction in the BCM (Body Control Module), which requires connecting to a computer to check fault codes. First, try disconnecting the negative battery terminal for three minutes to reboot the system—this often provides a temporary fix. If that doesn't work, you'll need to remove the door panel to inspect the actuator. At a repair shop, replacing the entire lock mechanism plus labor costs around 400 yuan. Don't be fooled into replacing the entire BCM module!

[DeSienna]

Master Chen from the neighbor's auto repair shop once talked to me about this common issue with the Excelle. The key is to check for oxidation on the contacts of the driver's side door lock controller. The design flaw in the Excelle allows rainwater to seep in and corrode the circuit board. Spraying WD-40 on the connector interfaces might help, but it's only a temporary fix. The trunk wiring harness breaking is also worth noting, as pulling on the harness when going over bumps can cause the unlock signal to malfunction. Stuck buttons on the remote can also trigger false signals; simply disassemble the remote and clean the contacts with alcohol. Aging electronic systems in older cars are inevitable, and if all else fails, pulling the door lock fuse to switch to manual mode is the most cost-effective solution.

[VanHector]

From an electronic repair perspective, the Buick Excelle has multiple sources of unlocking interference. Water ingress causing a short circuit in the keyhole micro switch can continuously send unlock signals, and the anti-theft module on the left side of the dashboard is also prone to moisture failure. There was a case where an aftermarket GPS installation caused signal interference, and the issue was resolved after removal. Use a multimeter to measure the voltage of the door switch line; if it's below 10 volts, it indicates a leakage in the circuit. For those who have modified their audio systems, pay special attention to poor grounding of the amplifier power supply, as it can interfere with CAN bus signals. It is recommended to first disconnect all aftermarket electrical devices before testing.