This tip usually refers to a hidden or “long-press” function on a car key fob (remote control), and what it does depends on the car brand.
Holding a button for about 5 seconds commonly triggers extra features such as:
- Lock / Unlock all windows (global convenience function)
On many cars, holding the unlock button opens all windows, and holding lock closes them. - Remote trunk/boot release (on some models)
A long press may open the trunk instead of just unlocking it. - Panic alarm activation
Holding the alarm button can trigger the horn and lights for emergency attention. - Signal reset / resync behavior (rare)
In some vehicles, long presses help the key fob re-establish communication with the car.
The exact function varies a lot between manufacturers and even between models of the same brand. If you tell me your car model, I can explain exactly what that 5-second press does for your specific vehicle.