The anti pinch sensor is a safety feature and part of the car alarm system. Used in cars with electric windows, its function is to detect when something obstructs the window or someone tries to break into the car through the window.
The anti pinch sensor is situated in the seal around the window and it is specifically set to detect when an obstruction or intrusion happens in the space between the edge and frame of the window.
In the case of an obstruction, the anti pinch sensor is in place to avoid, for example, an arm being trapped in the window as it automatically shuts and it does this by measuring the amount of power being used to close the car window. If the anti pinch sensor detects extra power is being used to close the window, the system assumes that there is an obstruction preventing the window from closing properly. The electrics of the car are either automatically disabled or the motor used to power the window forces it to change direction. In the case of an intrusion, when the car is parked, the anti pinch sensor detects an obstruction, for example a hand or tool forcing entry, in the gap between the door frame and window, and this triggers the alarm.
If the anti pinch sensor is damaged or faulty you may experience symptoms such as the window not moving up or down, or it may move in short bursts and stop and start a lot, or you may need to keep pressing the button to get it to work. You will receive a warning light on the alarm system if there is a fault with the anti pinch sensor or if it is damaged in any way. Sometimes the anti pinch sensor can malfunction if it has been subjected to water or dirt, being located in the window seals this can be a problem. Due to the safety features of this device it is advisable to seek professional advice and, if necessary, replace the anti pinch sensor as soon as possible.