Circuit/System Description

WARNING: This page is about a different car, the 2007 Saturn Outlook. However, it is still accessible from the selected car via links, so may be relevant.

The liftgate object sensor uses two tape switches embedded in the liftgate opening weatherstrip to detect any foreign objects in the path of the liftgate. When pressure is applied to the weatherstrip, the tape switch is closed signaling the power liftgate module (PLGM) that an object is in the path of the liftgate. The PLGM will reverse the direction of the liftgate motor should this occur.

The 2 tape switches are placed in series between the liftgate object sensor signal circuit and the liftgate object low reference circuit. Each object sensor has a resistor as well as a switch. The resistors enable the PLGM to perform diagnostic functions on the circuits. When both switches are open, voltage supplied by the PLGM passes through the resistors and supplies the PLGM with a reference voltage. If an object is in the path of the moving liftgate, the affected switch would close. The closing of the switch would bypass the resistor and change the reference voltage seen by the PLGM, indicating that one of the switches is closed and an object has been detected.